Ultralight compression to keep your pack spacious and light. When you need to compress your bulky gear without significantly adding weight, the Ultra-Sil Compression Sacks are the perfect choice. Made from high-strength 30D siliconised CORDURA fabric they can be compressed to one third of the original volume. Ideal for use inside your pack or travel bag when you need to compress clothing or bulky soft items to allow space for other essentials - or luxuries. The size range includes two extra small sizes good for compressing and storing down jackets and other clothing. Ultra-SilUltra-Sil is a very light nylon fabric. The outer shell is surrounded by a silicone layer; the inner layer is PU coated.
Ultralight compression to keep your pack spacious and light. When you need to compress your bulky gear without significantly adding weight, the Ultra-Sil Compression Sacks are the perfect choice. Made from high-strength 30D siliconised CORDURA fabric they can be compressed to one third of the original volume. Ideal for use inside your pack or travel bag when you need to compress clothing or bulky soft items to allow space for other essentials - or luxuries. The size range includes two extra small sizes good for compressing and storing down jackets and other clothing. Ultra-SilUltra-Sil is a very light nylon fabric. The outer shell is surrounded by a silicone layer; the inner layer is PU coated.
in 2 offers
last seen 15 May 2026
The lowest price we last saw for Sea to Summit Ultra Sil Compression Sack XL Blue was $43.99 at Techinn.com, compared across 2 retailers (last seen 15 May 2026). Prices may have changed since.
The all-time low we recorded was $42.00 on 27 July 2023.
Prices last updated 15 May 2026.
Sea to Summit Ultra Sil Compression Sack XL Blue
Ultralight compression to keep your pack spacious and light. When you need to compress your bulky gear without significantly adding weight, the Ultra-Sil Compression Sacks are the perfect choice. Made from high-strength 30D siliconised CORDURA fabric they can be compressed to one third of the original volume. Ideal for use inside your pack or travel bag when you need to compress clothing or bulky soft items to allow space for other essentials - or luxuries. The size range includes two extra small sizes good for compressing and storing down jackets and other clothing. Ultra-SilUltra-Sil is a very light nylon fabric. The outer shell is surrounded by a silicone layer; the inner layer is PU coated.
Ultralight compression to keep your pack spacious and light. When you need to compress your bulky gear without significantly adding weight, the Ultra-Sil Compression Sacks are the perfect choice. Made from high-strength 30D siliconised CORDURA fabric they can be compressed to one third of the original volume. Ideal for use inside your pack or travel bag when you need to compress clothing or bulky soft items to allow space for other essentials - or luxuries. The size range includes two extra small sizes good for compressing and storing down jackets and other clothing. Ultra-SilUltra-Sil is a very light nylon fabric. The outer shell is surrounded by a silicone layer; the inner layer is PU coated.
Last updated at 15/05/2026 17:03:03
Sea To Summit Ultra-sil Compression Bag Blue 30 Liters
Delivery $19.99
Ultra-Sil Compression Sack Superseded
Delivery $9.95
originally posted on REI
Used with my women's 20F down sleeping bag. I've been using this stuff sack for almost a year with 0 issues. Great for backpacking, easy to stuff, easy to unpack, super lightweight. Not waterproof, but I personally do not find a waterproof stuff sack to be necessary so long as you have a good backpack rain cover.
originally posted on altitude-sports.com
Ordered a medium (about 9 litres) to hold my summer down bag which originally has the same size stuff sack, but now easily compresses down to half size. For my summer backpacking and motorcycling camping kit, I find three of the medium bags work well: one for sleeping bag and liner, one for regular clothes, and one for warm gear like puffy jacket, toque, etc. Meant to order a three Ultra-Sils as shown above but accidentally ordered ordered a variant which is slightly heavier and made with a stiffer, waterproof fabric. Still a good, lightweight compression bag. Strap/lid system identical on both types and easy to use.
originally posted on REI
I love these things– this is my third one! When first looking for a compression sack for my sleep system I tried this and an Osprey Straightjacket bag. I can see where the Osprey shape would be preferable in a small suitcase or something where you have limited vertical stacking space, but the REI bag is much, much more compressive and works well in soft bags (like a duffle). You can really cinch things down with the four straps and I've found the material to be durable. I used the 15L version on a cross-country bike ride to store my 50 degree sleeping bag, a travel sheet, and my Nemo Fillo. It all fit and compressed down several inches, and even better the bag showed no signs of wear and tear after packing it full and cinching it down tight 70 days in a row. I also ... MoreI love these things– this is my third one! When first looking for a compression sack for my sleep system I tried this and an Osprey Straightjacket bag. I can see where the Osprey shape would be preferable in a small suitcase or something where you have limited vertical stacking space, but the REI bag is much, much more compressive and works well in soft bags (like a duffle). You can really cinch things down with the four straps and I've found the material to be durable. I used the 15L version on a cross-country bike ride to store my 50 degree sleeping bag, a travel sheet, and my Nemo Fillo. It all fit and compressed down several inches, and even better the bag showed no signs of wear and tear after packing it full and cinching it down tight 70 days in a row. I also love that the bag doesn't need to be full to be compressive– you could just put a puffy in here and it would pack down because of the strap design.
| Special feature | Water Resistant |
| Product care instructions | Machine Wash |
| Hand Orientation | Left/Right |
| Length | 10 inches |
| Season | Year-round |
Sea To Summit Ultra-sil Compression Bag Blue 30 Liters
Delivery $19.99
Ultra-Sil Compression Sack Superseded
Delivery $9.95
Used with my women's 20F down sleeping bag. I've been using this stuff sack for almost a year with 0 issues. Great for backpacking, easy to stuff, easy to unpack, super lightweight. Not waterproof, but I personally do not find a waterproof stuff sack to be necessary so long as you have a good backpack rain cover.
Ordered a medium (about 9 litres) to hold my summer down bag which originally has the same size stuff sack, but now easily compresses down to half size. For my summer backpacking and motorcycling camping kit, I find three of the medium bags work well: one for sleeping bag and liner, one for regular clothes, and one for warm gear like puffy jacket, toque, etc. Meant to order a three Ultra-Sils as shown above but accidentally ordered ordered a variant which is slightly heavier and made with a stiffer, waterproof fabric. Still a good, lightweight compression bag. Strap/lid system identical on both types and easy to use.
I love these things– this is my third one! When first looking for a compression sack for my sleep system I tried this and an Osprey Straightjacket bag. I can see where the Osprey shape would be preferable in a small suitcase or something where you have limited vertical stacking space, but the REI bag is much, much more compressive and works well in soft bags (like a duffle). You can really cinch things down with the four straps and I've found the material to be durable. I used the 15L version on a cross-country bike ride to store my 50 degree sleeping bag, a travel sheet, and my Nemo Fillo. It all fit and compressed down several inches, and even better the bag showed no signs of wear and tear after packing it full and cinching it down tight 70 days in a row. I also ... MoreI love these things– this is my third one! When first looking for a compression sack for my sleep system I tried this and an Osprey Straightjacket bag. I can see where the Osprey shape would be preferable in a small suitcase or something where you have limited vertical stacking space, but the REI bag is much, much more compressive and works well in soft bags (like a duffle). You can really cinch things down with the four straps and I've found the material to be durable. I used the 15L version on a cross-country bike ride to store my 50 degree sleeping bag, a travel sheet, and my Nemo Fillo. It all fit and compressed down several inches, and even better the bag showed no signs of wear and tear after packing it full and cinching it down tight 70 days in a row. I also love that the bag doesn't need to be full to be compressive– you could just put a puffy in here and it would pack down because of the strap design.
I used this sack for two weeks in 2022 and it works great. A compression sack needs strong, slippery fabric and very strong stitching and straps. This sack has it. It compresses my 0C degree synthetic bag down to a little smaller than a soccer ball. It compresses my -10C down OGC quilt even smaller. I have a similar sized OR compression sack and this one works just as well.
This review is for the 14L, Medium compression sack.I decided to buy a compression sack after using one with a rented -15 degree Celsius bag, and being amazed at how much it shrunk that monster down.Weight: 5 oz compared to 1 oz for a typical sleeping bag stuff sack. I would have preferred not having the waterproof lining. Would have saved a few ounces and I don't need it because I use an overal waterproofing sack for my backpack.Compression:1) took my 40-degree Kelty bag from 10.5"H x 7.5"W (464 cu in) to 6"H x 8.5"W (340 cu in).2) took my 20-degree REI lumen bag from 15"H x 7"W (577 cu in) to 8"H x 9"W (509 cu in).Compression achieved by kneeling on the sack as I repeatedly turned it and tightened the straps. As you go make sure to slide a finger under the ... MoreThis review is for the 14L, Medium compression sack.I decided to buy a compression sack after using one with a rented -15 degree Celsius bag, and being amazed at how much it shrunk that monster down.Weight: 5 oz compared to 1 oz for a typical sleeping bag stuff sack. I would have preferred not having the waterproof lining. Would have saved a few ounces and I don't need it because I use an overal waterproofing sack for my backpack.Compression:1) took my 40-degree Kelty bag from 10.5"H x 7.5"W (464 cu in) to 6"H x 8.5"W (340 cu in).2) took my 20-degree REI lumen bag from 15"H x 7"W (577 cu in) to 8"H x 9"W (509 cu in).Compression achieved by kneeling on the sack as I repeatedly turned it and tightened the straps. As you go make sure to slide a finger under the crescent shaped edges to keep them from digging into the bag.Conclusions:Is the extra 4 oz worth it? It depends. The sack was much more effective at volume reduction on the Kelty bag. It reduced the volume of the warmer REI bag only slightly, but it did change the shape from tall and narrow to short and squat. This may be useful depending on the shape of the space allocated for a sleeping bag in your backpack.
I go Motocamping (like "Car camping" but on a motorcycle), so space is at a premium. I have a pack that I can mount on my tail rack, but up until now I have had to strap my sleeping bag to the passenger (pillion) seat. I hate that.So I have been looking for a way to make my sleeping bag more compact, so I can put it inside the pack. I tried buying a "warm weather" sleeping bag, which compressed down so small it fits in my saddlebag...but the bag size was so small (I have big shoulders and chest) that I felt like I was being wrapped for my burial rites. I returned that and started looking for a way to compress my Kelty Discovery 30 (also purchased at REI), which is so roomy. Online reviews (for instance, that website named after a South American River) for cheaper ... MoreI go Motocamping (like "Car camping" but on a motorcycle), so space is at a premium. I have a pack that I can mount on my tail rack, but up until now I have had to strap my sleeping bag to the passenger (pillion) seat. I hate that.So I have been looking for a way to make my sleeping bag more compact, so I can put it inside the pack. I tried buying a "warm weather" sleeping bag, which compressed down so small it fits in my saddlebag...but the bag size was so small (I have big shoulders and chest) that I felt like I was being wrapped for my burial rites. I returned that and started looking for a way to compress my Kelty Discovery 30 (also purchased at REI), which is so roomy. Online reviews (for instance, that website named after a South American River) for cheaper compression bags were scary...the last thing you want from camping equipment is to find out they fail when you are on your trip. I bought the REI 20L version and stuffed my Kelty in, then began working the compression straps. By the time I had the straps reasonably tight, the bag was 9" diameter by 14" long, in spite of this being a synthetic fill bag. It fits in my pack with room for my tent, ground cover, airmat, air pillow and LED lantern...SUCCESS!!!! The material of the bag and straps were able to do this without any obvious signs of strain. You get what you pay for...spend the extra and get one of these from REI, instead of cheap imitations online, so you can trust it, especially when returning a defective product AFTER the trip doesn't help you DURING the trip.
The 20L compression sack capable of reducing the bulk of your clothing, most 3 season sleeping bags and tents. The stiching around the seams and the straps is nice and tight to provide the durability needed to handle the compression pressure in a lightweight sack. This compression sack is not designed to be waterproof, merely water resistent and it has preformed very well protecting my clothing from condesation on a recent backcountry snowshoe trip. I plan on purchacing smaller variations for my bikepacking adventures.
I have a few compression sacks and this one is easily the best quality material and stitching. The top piece is sewn on one side to the main body so it isn’t only connected by the straps. This fits my -22 degree down bag with ease and compresses to half the size so it will likely fit my bag liner as well. Good buy and the price is right.
This is the product I needed but never knew I needed until I stopped by my local REI store. I'm an old school camper getting back into it, and a lot has changed. Was talking to an REI sales associate about packing things compactly for a cross-country motorcycle tour I'm taking in June, and found out that I'm packing my sleeping bag wrong. I used to fold it in the middle and just roll it, but come to find out that when you fold the sack the same way every time you break the internal fibers in the same place every time resulting in a cold spot. Better to stuff it than fold and roll so that the internal fibers break more randomly.With that misperception fixed, the problem then became how to store my bag as compactly as possible, and the answer was the REI Compression ... MoreThis is the product I needed but never knew I needed until I stopped by my local REI store. I'm an old school camper getting back into it, and a lot has changed. Was talking to an REI sales associate about packing things compactly for a cross-country motorcycle tour I'm taking in June, and found out that I'm packing my sleeping bag wrong. I used to fold it in the middle and just roll it, but come to find out that when you fold the sack the same way every time you break the internal fibers in the same place every time resulting in a cold spot. Better to stuff it than fold and roll so that the internal fibers break more randomly.With that misperception fixed, the problem then became how to store my bag as compactly as possible, and the answer was the REI Compression Stuff Sack. I was shocked that the 21 liter bag was so light and so tough. It holds my sleeping bag and cinches down into a very compact bundle, squeezing all the air out of the bag. The result is a lot more room for other cargo. Brilliant solution to a problem.I'm actually going to buy a couple more of the sacks in various sizes to save even more space, and on a bike going cross country, space is at a premium.Thanks to REI for helping me think outside my box in a very practical way, and hooking me up with a great product.
I now have 4 of these compression sacks in various sizes as they are a great way to save space for ultralight backpack trips. Use them to crank down my sleeping bag, and tent with fly to a more manageable size which sets up my whole backpack for a better and easier packing experience. The sacks are very light cordura material and are under a lot of stress when tightly packed but have proven very durable so far. These are expensive but they work very well so recommend them highly if you are working on trimming down your load size for backpacking trips.
| Special feature | Water Resistant |
| Product care instructions | Machine Wash |
| Hand Orientation | Left/Right |
| Length | 10 inches |
| Season | Year-round |
