Ultra-Sil Day Pack

It stuffs down to a size smaller than a baseball. Its manufacturer, Sea to Summit Inc. of Perth, Australia, suggests using it as a keychain. But unpack the Ultra-Sil Day Pack and its crinkly “siliconized” Cordura nylon quickly takes shape, a backpack materializing from a tiny ball right in front of your eyes.

As outdoors products go, the Ultra-Sil Day Pack is certainly strange. It is far from technical gear. The backpack, a basic sack equipped with shoulder straps, carries its stowed items with scant support. Lumps protrude from the thin fabric where a shoe or a water bottle might be stuffed inside. Objects dig into your back.

Sea to Summit Backpack.jpg

Sea to Summit Ultra-Sil Day Pack

But what this $28 backpack lacks in performance it gains in improbable convenience. The Ultra-Sil Day Pack weighs just 2.4 ounces. It fits in any pocket. Unzipped and open, there’s about 20 liters of space inside — enough area to stow a day’s worth of supplies while travelling.

The company (www.seatosummit.com) markets the Ultra-Sil as a “super strong pack that clips on your keychain to shoulder groceries or scramble a summit.” You could easily put it in your pants pocket and bike to the store, load in groceries, and wear it home.

Other uses for the water-resistant pack include carrying wet gear after a day outside. Stash your sweaty clothes in the pack after a triathlon or other event. The company mentions using the pack for “messy stuff” like dirty laundry after a weekend of camping.

Sea to Summit Ultra-Sil Day Pack.jpg

Ultra-Sil Day Pack compacted into its case

I might think twice before scrambling to the aforementioned summit with this pack. But in a pinch, if the Ultra-Sil is what’s available, this siliconized sack with shoulder straps can do the job. It can carry water, food, some gear, and extra clothing layers for a hike.

Indeed, Sea to Summit has tested the pack for maximum weight. The fabric used for the pack, which has bar-tack reinforced stitching at stress points, resists loads of up to 350 pounds, the company cites. But a company representative said this much weight far exceeds suggested use amounts. The spokesperson expanded, “It’s likely they’ll cut their arms off before they reach their destination.”

—Stephen Regenold writes about outdoors gear at www.gearjunkie.com.

Posted by David - 01/13/2010 10:54 AM

You forgot to mention one of the greatest uses of this bag;
Shove it in your suitcase when traveling. It’s perfect for those trips that are not hiking vacations but there may be a walk in the mountains or a trip to the open air market.
Also, Its been to the gym a dozen times already with me since I received it from a good friend for Christmas!

Posted by Scott - 01/14/2010 03:50 PM

Good idea, but I have some doubts about the durability.

Hammock Bliss makes one that may not fit on your keychain, but it won’t blow out either. This always travels with me.


Also, REI has a “house brand” sack that has gotten pretty good reviews.

Posted by Bernard - 07/23/2010 04:34 PM

I’m buying this to keep on my motorcycle keychain. You never know when you may need to bring something home that you didn’t count on.

Posted by Pedro Kozlakowski - 05/09/2013 01:19 PM

As a day-to-day cyclist, I could use one of these to put my cycling shoes away and feel a little more comfortable. And also whenever I go camping with my scout troop, I’d come in handy.

Posted by franko - 05/09/2013 01:20 PM

This would be great for bringing my work clothes to work while bike/train commuting. My messenger pack is overkill, takes up a lot of space & is like riding with a kite on my back. Something sleek & pocketable like this would make my commute a lot easier!

Posted by Osvaldo Orsini - 05/09/2013 01:21 PM

Easy! As a summit pack! You carry it on with all your stuff and on summit day, break out the USDP, put in some bars, water, first aid kit, headlamp and fleece and head up there.

Posted by Tiara - 05/09/2013 01:22 PM

This could be great to throw all the poison ivy, tick infested, smelly clothes/shoes in, after a long day of Adventure Racing!

Posted by Kristin Troska - 05/09/2013 01:24 PM

Awesome looking “Useful Bag”! I need this bag to take to CONvergence (Four day annual convention in Bloomington MN for fans of Science Fiction and Fantasy in all media). I would be the envy of the other 5,000 attendees, and I would tell each and every one of them about Gear Junkie! This bag could hold my water bottle, snacks, books, and spare socks for the convention. Thanks for the chance to win.

Posted by Pamela Burns - 05/09/2013 01:24 PM

This would rock,while hiking w/ my dog,up Cache Creek
To store our snacks,water,&lunch in! Thanks.

Posted by Angel Velez - 05/09/2013 01:24 PM

Excellent as to carry my EDC items & first aid kit when I go hiking.

Posted by Philip Hogan - 05/09/2013 01:24 PM

I always have a need for a bag with me. Weather I’m out geocaching or at the store. It would also be great to have on the jet ski or the boat when you need a little extra help carrying stuff back off the lake.

Posted by JasonV - 05/09/2013 01:26 PM

Because, like my scout leader always said: “Always be prepared.” That has served me well all during adulthood. And because they can pack down into such a cool little bundle.

Posted by Ted B. - 05/09/2013 01:26 PM

I need this pack for holding my packraft and hand paddles as I run to the local river put-in and packraft back to the take-out. Local last minute adventures wherever you go!

Posted by Kelly - 05/09/2013 01:26 PM

Great little pack! I’d love to have one of these for both hiking/camping but also for cycling. Light weight, high compressibility, great load capacity. Excellent!

Posted by melanie swanson - 05/09/2013 01:32 PM

It would be perfect for when the Boy Scout Troop is out on adventures. I would love these for the entire troop !!

Posted by Edward Steele - 05/09/2013 01:33 PM

The locals where I work are interesting so I walk with the company receptionist at lunch four days a week. Friday I walk alone and there is a bit of open space about a mile from my desk with a rock face above a kettle pond. If I race up there I can sit down and for a short time pretend I’m in the wilderness. A pack like this would make it easier to carry my lunch.

Posted by Tim Ahlstrom - 05/09/2013 01:33 PM

Ahh, I could use something like this for a day scouting pack when pack in to a wilderness area or when I ride my bike down to the grocery store and discover the pannier is too small…

Posted by Jessica Black - 05/09/2013 01:36 PM

I’d love to have this tiny extra pack for my keychain. You never know when you’ll need to carry more than you expected! And waterproof is a great feature for my summers in Scotland.

Posted by Don Theisen - 05/09/2013 01:40 PM

I need this pack because everytime I use it I can tell a great story that starts with, “When you subscribe to the Gear Junkie great things happen…..”

Posted by BeerCyclist - 05/09/2013 01:40 PM

Seems like a great bag for packing up my trail running gear. I tossed out an old gear bag about a month ago because somehow my car keys fell out of it. Sadly, they fell out somewhere in the 20 feet between my house door and the car and haven’t been seen since. Not sure how that’s even possible, but this bag, thanks to being able to clip to a keychain, appears to be the solution I’ve been looking for.

Posted by CRAusmus - 05/09/2013 01:41 PM

Excellent for day trips from your hotel while traveling. It’d probably get more use out of me while Peakbagging from base camp though.

Posted by jan - 05/09/2013 01:52 PM

I would like to win this pack so that I can, next to treats for my dogs and “the essentials” for my gf actually bring along a little something for me as well that does not fit into my current backpack.. ;)

Posted by Abigor - 05/09/2013 01:52 PM

A bag like this would be great when the civilians of the world turn into zombies. Running away the bag is light enough the zombies arent likely to catch up , and strong enough that it wont tear with the apocalyptic creatures pull on it.

Posted by Gdavis - 05/09/2013 01:57 PM

I am used to working with a much bigger one but sometimes you wish you had a smaller one to get the job done nice and quick. And this looks like a nice and quick one. SOLD

Posted by Josiah Spencer - 05/09/2013 02:03 PM

Me and this pack would go from the surf then on my bike ride to the gym, in my two favorite colors green and yellow. Josiah Spencer

Posted by Bryan A. Overn - 05/09/2013 02:22 PM

This bag would be awesome for my wife and I, with our many, upcoming, planned adventures. With trips planned over the next 2 years to Norway, Belize, Fiji, Nepal, and Northern Canada, this bag would easily transport during flights, and be EXTREMELY useful for life in general.

Posted by Jennifer Chamberlain - 05/09/2013 02:23 PM

Stuffs down to a size smaller than a baseball? AWESOME! Sounds like a must have! :)

Posted by Val Kowalewich - 05/09/2013 02:23 PM

Well – this pack will replace my old sling style heavy hemp hippie man-bag and make me look stylish at the farmers market or the mountain top. Compact, ample storage for anything from my cigars to crap-apple preserves. I could even put my hibachi in there!!!!

Posted by Joanne Cassidy - 05/09/2013 02:26 PM

Perfect for walking the camino in Spain.since I’m a 66 spunky granny I think I deserve it!

Posted by tash - 05/09/2013 02:29 PM

i got a little boy, he’s busy like me. we go hiking and biking and occasionally climb a tree. drinks and snacks are a must, we’d fill this bag and it wouldn’t bust! and the yellow colour reminds me of a sunny day! :)

Posted by clayton dewberry - 05/09/2013 02:32 PM

This is a great pack. You can stuff it down to the size of a pair of socks and carry it along to use as a summit bag; you can put it in your car and pull out it when you need to buy groceries or pick up some organic veggies at the farmers market; its super light weight, pretty darn durable; and provides an ample amount of storage. I used mine on the last mile of the summit of Mt. Whitney last summer. My kids are always taking mine…

Posted by Ben Matheson - 05/09/2013 02:50 PM


Posted by Jeremy Abraham - 05/09/2013 03:03 PM

I will be going to British Columbia this summer to do some backpacking around glaciers and glacial lakes. We are planning to have some day hikes, and I don’t wan’t to use my 75 liter pack for a day trip, and I want to keep my stuff safe from the ice and frigid water. This pack would be super light, super secure, and a great size for those day trips, and it would be a pleasure to take it along with me!

Posted by Jordan - 05/09/2013 03:18 PM

The perfect run-to-the-gym backpack. Lightweight, packable, and useful for smelly gym clothes or post-workout errands. If you need it, it’s there.

Posted by Dave - 05/09/2013 03:30 PM

I could ditch my top cap and save some weight by switching to this little gem. It would be perfect for side hikes!

Posted by Gearry Judkins - 05/09/2013 03:33 PM

This is exactly what I need for paddle trips. I like to get out of the boat and take a short hike now and then, and just need to bring along a few essentials. I hate to carry a regular daypack for just a few short uses, or carry a large drybag just for a water bottle, first aid kit, and a snack. This is small and light enough to go in a dry bag or even my overnight backpack and forget about until I decide to strike off, and don’t feel like carrying ALL of my stuff. Perfect.

PS- I should also win because my initials are GJ, and I am a Gear Junkie. Worth a shot…

Posted by Kevin - 05/09/2013 04:25 PM

I believe that when my wonderful wife looks upon me instead of seeing the bearded man that I am, she sees me as a pack mule (at times a spider killer as well). This is partially my own fault for establishing the role as official family sherpa when we started dating, but a problem often arises when we encounter stuff we want or need. I’m almost always limited to what I can carry by having only two arms and small pockets on most of my clothes. And since I don’t like carrying empty bags on my back in case something strikes her fancy, there’s almost no solution in site. Until now…

Posted by Zach Raney - 05/09/2013 05:21 PM

I could use one of those while day hiking off the prince William sound on my 75 day Alaska expedition with nols :)

Posted by Bryan L. - 05/09/2013 06:34 PM

This actually sounds useful as a human bus/bike train I can see this coming in handy when I go to pick up the kids from school and they are bringing home a big art project I wasn’t expecting. Just pull this puppy out and instant trunk space on the bike. Or the impromptu stop at a farmers market and discovering peaches are ripe early. The uses seem endless, perhaps I’ll get to try this out…

Posted by Kelsey - 05/09/2013 06:41 PM

I like the idea of biking to the grocery store. I could use this bag to carry by snacks…it could be my snack pack! :)

Posted by Damian - 05/09/2013 08:38 PM

When you walk around the city you need a waterproof bag 4 save your laptop. In the forest to save map and robe. Climbing to put the food and the vine for the top. Sailing to protect the GPS. I don’t know where I’ll am next time. I prefere have a Ultra-sil always with me.

Posted by Nathan Swann - 05/09/2013 10:31 PM

I would love to add this to my kayak gear. Space is limited and this would be great to throw in a day hatch and use it for a day pack when I explore the barrier islands. The fact that it is compact, lightweight and water resistant would make it a perfect addition.

Posted by Jake Ferguson - 05/09/2013 11:42 PM

I could use this for paddling, biking and hiking (like everyone else) but really the possibilities are endless. A few other uses that come to mind are rescuing small mammals from trees, transporting my latest basil harvest or carrying my grandmother’s “special” items on our Sunday outings.

Posted by Hunter - 05/10/2013 10:33 AM

I need this pack because I’m a poor college student going on a 6 week field camp where all we do is hike this summer. It’s going to test me and my equipment.

Posted by David Logsdon - 05/10/2013 01:20 PM

Would keep me more organized on the trail.

Posted by Craig Porzondek - 05/10/2013 01:25 PM

I was in a car accident five years ago and lost the ability to hike. I use to do 500 miles per summer but now I am only able to walk 2.75 miles per day. I always carry and emergency pack with te essentials and am always looking for ways to lesson the weight. This day pack is exactly what I need to continue my progress towards getting back on the trail.

Posted by sheila bergin goss - 05/10/2013 01:26 PM

My daughter just had serious surgery for TMJ; carrying a heavy backpack has been problematic..this lightweight pack seems like an awesome solution!

Posted by Joseph Martin - 05/10/2013 01:29 PM

I could use one for Hiking, Hunting and Fishing with my boys. It never fails, somebody is gonna get muddy. This would be awesome to throw some clothes in for the return trip. It could carry clean clothes there and the dirty clothes back.Not to mention a little extra room for the first aid kit.

Posted by Justin Schuetz - 05/10/2013 01:29 PM

I often carry a ‘drawstring’ backpack around in my seat bag as an emergency ‘extra storage’ solution while on the bike. Nice to carry a 6 pack on your back instead of precariously on your handlebars while going the 5 miles from the liquor store to the beach after work. This looks even smaller and lighter with better straps than a drawstring pack. Great work Sea to Summit!

Posted by J. Blakley - 05/10/2013 01:29 PM

It’ll keep me lean, fast and on-the-go.

Posted by Alex - 05/10/2013 01:30 PM

I need this pack because I have four outdoor children and I am tired of hauling around I diaper bag! I could look cool for once if I had this!!

Posted by Erik K. - 05/10/2013 01:31 PM

I’m a Revolutionary War reenactor and this would be a great way to carry my kit to camp and then make my modern equipment “disappear”.

Posted by Karen Phillips - 05/10/2013 01:31 PM

My husband and I are day trippers and it never fails we find a cool place to hike for an hour our two and do not want to haul our sturdier backpacks everywhere we go… just like to pack light
( water, binoculars and snacks ) and impulsively :)

Posted by Clemente Oriciaga - 05/10/2013 01:31 PM

I could use this bag as a beginning bag for camping trips which I would like to start doing this summer, but haven’t due to lack of experience and equipment.

Posted by Robert Eld - 05/10/2013 01:32 PM

The uses and convenience this pack offers are endless! It would be great for use going to and from the local produce stand/market, going along on treks with the dog along the trail or on the bike for rides, perfect for storing or safe-keeping for surprise rainstorms on a motorcycle, it would be ideal for a “go along” bag on the many trips I take every year for work as a travel agent all over the world and all conditions. This bag is the answer to so many needs for everyone!

Posted by Bjorn - 05/10/2013 01:33 PM

I’m constantly in need of “just a little more space”, and since I shredded my last musette bag that hung out in the bottom of my pannier, I’ve been caught without enough capacity more than once. I’ve also gotten in the habit of taking the bare minimum for most adventures, and this might be the perfect way to reduce that mass a little more on lightweight overnights on foot.

Posted by Amy - 05/10/2013 01:35 PM

I just moved out of the city and into the wilderness for graduate school. I’m noticing that the cheap gear I currently own isn’t made to last a while, and I’m going to need something that will make it until I have my Master’s degree. I’ll probably have to tote around some textbooks with my gear, but this pack looks positively wonderful.

Posted by Vanessa Fielding - 05/10/2013 01:43 PM

I would use this pack almost everyday! Ive hiked 14ers in Colorado and didnt habe a nice pack like this one! I rock climb and hike around Devils Lake weekly so this would be amazing to have then I could finally retire my school back pack that is almost 10 years old! :) Please pick me!

Posted by Alexandre - 05/10/2013 01:44 PM

I need this pack because when i’m traveling with my big 70L. backpack, I always bring my smaller day pack(which still take a lot of place) for walking around, My day backpack is awesome and all, but its a real pain when it comes to changing locations: I have the huge 70L. pack on my back and the 30L. day pack on my front. With this awesome Ultra sil day pack, I can just fold it up and put it in my pocket, or use it as padding for beer mugs and such in the larger pack on my way back home!

Posted by Michael Brooks - 05/10/2013 01:49 PM

Would make my daily journey, more comfortable.

Posted by Dylan - 05/10/2013 01:56 PM

Let me explain why this pack would prove useful for me.

My brother and I have spent the last 18 months design and constructing a time machine. We have laboured both mentally sand physically collecting parts and simulating tests over the computer. We should be putting on the finishing touches next week and I have drawn the short straw to guinea pig it.
We’ve arranged for only ourselves to be transported through the time machine during our simulated computer experiments. We’ve also tested many times with “carry-on” object to no avail. That’s where you come in!
The Sea to Summit Ultra-Sil Day Pack would be the perfect piece of gear to travel through time with me! With it’s ability to compact into an seemingly invisible physical state is unparalleled technology! The pack will allow for storage of essential items along my journey and will also mystify and excite the folk of the time era in which I’m travelling to (still undecided).

Please consider my plea for help!

Posted by Brent - 05/10/2013 01:57 PM

This pack would be great for my backpacking trips to try and stay as light weight as possible!

Posted by Jeremiah Weakley - 05/10/2013 02:00 PM

this would be PERFECT for keeping in my windshield bag on my bike. then in a pinch if I ever needed to haul something bigger than my pocket, I’ve got a full sized backpack at my fingertips!! genius for bikers!!

Posted by Mark Sandoval - 05/10/2013 02:01 PM

I don’t need this very cool day pack. But I certainly want it. Perfect compliment for the day hikes I take with my 3 year old son!

Posted by Tim @ Appalachia & Beyond - 05/10/2013 02:01 PM

That would make for an excellent drop bag during ultra trail marathons I plan on running in the very near future.

Posted by Paula - 05/10/2013 02:05 PM

I’d give it to my husband for Father’s Day so he could use it when he is SUP boarding on the lake and needs a light weight water proof bag to safely store some items on his back…he falls a lot.

Posted by Lane Martin - 05/10/2013 02:07 PM

I’d keep it in my day bag for those Cub Scout day hikes where someone forgets a pack or brings a friend who didn’t have a pack.

Posted by Andy O. - 05/10/2013 02:15 PM

My daughter is small and could use a lightweight pack. Most of the regular ones are so heavy even when they are empty they become quite a drag for her.

Posted by Sean K - 05/10/2013 02:16 PM

so my pb&j stays dry

Posted by David Massing - 05/10/2013 02:26 PM

The pack looks awesome in its stored away key chain! I like this idea as a back up back pack. Very convenient!

Posted by Steve Klopp - 05/10/2013 02:26 PM

I’m 46 and I just signed up for a 27.4 mile trail run on the SHT. My pack could stand to loose a little weight.

Posted by Jer - 05/10/2013 02:37 PM

This is a great solution for those short scrambles where you don’t want to repack the top detachable hip sack of your 70L pack.

Posted by Christine - 05/10/2013 02:44 PM

This would be the perfect pack to solve my problem of stopping at the grocery store on my bike ride home from work and accidentally grabbing more than I can carry. It also looks useful for carrying a few essential items on day hikes from a base camp. Thanks for the chance to win!

Posted by Chad Januskiewicz - 05/10/2013 03:00 PM

This bag would be great to send to Nepal with my friend that is going over there to help with an orphanage. Maybe I could get some LuminAid’s to fill it with for the kids. :)

Posted by Lia Keller - 05/10/2013 03:17 PM

Hiking with kids often has me starting light and then bringing home sticks, rocks and much more that could nicely fill the pack!

Posted by Linda Johnson - 05/10/2013 03:21 PM

I’d love this just to stash in my car with my emergency gear, for one of those times you wish you brought a bigger bag to carry stuff in.

Posted by Nick - 05/10/2013 04:15 PM

Cycling year round in Seattle, my clothes just get to dang wet!

Posted by Doug Elliott - 05/10/2013 04:25 PM

Because in 49 days 13 hours 35 minutes and 28 seconds I will begin to climb mt Kilimanjaro!

Posted by Dana Sahm - 05/10/2013 05:26 PM

I need this for my September solo Yosemite backcountry trip! It would take up no room and not add any discernible weight to my pack but be available to quick side trips while on my adventure!

Posted by adam evans - 05/10/2013 06:10 PM

I need this because I dont always have bag, but often need one when I was carrying nearly nothing in the morning but bought something later-on and struggle to carry/ride home a few miles one-handed. looks good.

Posted by Alexander Tallmadge - 05/10/2013 07:09 PM

I’m starting a new job soon where I’m gonna be out doing trail maintenance for 5 days at a time, having a daypack that is easy to carry out would be a big help!

Posted by Jaclyn Marston - 05/10/2013 09:15 PM

I would love this bag because it’s a great summit bag. Just enough to stuff down and hang off your big bag until summit day. Enough to hold some trail mix and a hat, and easy to change. I’ve been needing a bag like this because the other summit bags take up to much room! But I do need one that is small enough, but that can still carry the goods. I climbed Mt. St Helens and my other bag just took to much space, this bag would be great for my next climb! Mt. Adams! :D

Posted by Deke - 05/11/2013 02:48 AM

This would be great for the sweaty gym clothes

Posted by Tracy Holman - 05/11/2013 06:46 AM

I am a small woman 5 feet 100lbs so this is the perfect pack for me. My sister & I are going to Alaska for 6 day guided hike @ this would be the perfect pack for the trip. Go girl power! Go sister power!

Posted by Tim - 05/11/2013 08:15 AM

this would be great to stash in your suitcase on vacation and than use as a carry on bag on your trip home with all your souvenirs and other stuff you picked up on your travels

Posted by Ben c - 05/12/2013 11:01 AM

An ultra sil day pack is the perfect thing to stuff in your down parka when walking through airport security with pockets filled to the brim with climbing gear or food, two carryons, and a helmet of some sort. Instantly transform to and from a 3rd carryon with no weight consequences.

Posted by Amy O - 05/13/2013 03:16 PM

Congrats to winning comments from readers Lane and Lia. Thank you to everyone who entered!

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