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  • Keeps your bag clean, saving it from the wear and tear inflicted by washing machines
  • Adds 8.4 degrees of warmth to your sleeping bag
  • Width tapers from 32" at the shoulder to 24" at the foot
  • Comes with stuff sack for convenient packing


View all Cocoon Sleeping Bag Liners

REI membership


Best Use Backpacking
Sleeping Bag Shape Mummy
Added Warmth (F) Up to 5 degrees
Added Warmth (C) Up to 2.8 degrees
Stuff Sack Size 3.5 x 7 inches
Material(s) CoolMax polyester
Dimensions 86 x 32(shoulder) x 24(at foot) inches
Weight 9 ounces
Weight - Metric 0.26 kilograms
Rated 5 out of 5 by from Great for adding warmth or alone in the summer I bought this liner to supplement my 20 degree sleeping bag on cold nights when I need a little more warmth, but don't want to bring my 0 degree bag with me. The liner is prefect for this purpose. I recently used it with my 20 degree bag when the temperature got down to around 30 degrees at night, and I could feel the difference compared to my sleeping bag alone. I also have used this liner as a stand-alone sleeping bag in the summer when I would have been way too hot using my regular bag. It provided the little extra warmth I wanted, but allowed me to be comfortable all night long. I highly recommend this product!
Date published: 2014-07-08
Rated 5 out of 5 by from Great for extra warmth! Will not go into the cold woods without this item! It makes my +20 degree bag really +20 degrees! If you like to sleep in your briefs and not all your clothing this item will help you do that. I started off a night in my briefs with temps in upper 30s. Around 3am the temp dropped to 26 degrees. I woke up some what chilled in my NF +20 synthetic bag. I slipped into the liner and stayed in just my briefs to see how it worked. WOW! I was toasty warm the rest of the night. It's also nice to not have to slip into that cold nylon either. Can't wait to use it for hot days instead of a big sleeping bag here in Texas. If you sleep kind of cold, GET THIS ITEM! You will love it!
Date published: 2009-03-05
Rated 5 out of 5 by from Won't Sleep Without It I bought this from REI about a year ago when I was headed out for a winter camping trip and looking for a little extra warmth. It does provide more warmth, but it's the comfort that I didn't expect. Slipping into this is like getting between really soft sheets. Now, I use this whenever I camp - winter, spring, summer, or fall. I recently used just the cocoon when I was camping out in mid-60's weather. I'm telling you, I'm kicking myself for camping so many years without the CoolMax Cocoon.
Date published: 2014-11-11
Rated 4 out of 5 by from I love this thing Very nice liner. I bought this last minute as I had planned an early Spring camping trip and the temperature took a turn on me. I was afraid the 30 degree bag I had wouldn't be enough so I bought this. The liner made my mummy bag warmer and much more comfortable. Also it is easier to wash than trying to wash an entire mummy bag. I've used it twice now and can't believe I went this long without one. Packs up nice and tight for cramming in a backpack.
Date published: 2013-04-18
Rated 5 out of 5 by from I Love This Bag! I love this little thing. At first I thought it was too flimsy; however, I beat the snot out of it and its still hanging in there! The Pros: 1) This saved me in my Cat's Meow for two reasons. First, it gave me added warmth when the temps dropped and second, it kept my stink off the bag. No other way to put it: when you are showerless for several days and in the same clothes...this little bag will protect your much more expensive sleeping bag from your reek. 2) Light and easy to shove in your pack - can't say anymore there. 3) Was great for climbing into in the middle of the day when I wanted to read my book but it wasn't super cold out. I look forward to using this around my house in the winter. The only con I could think of (but didn't warrant ditching the 5 stars): You can't move around in it much. Since that isn't what I bought it for, that wasn't a consideration for me. I thought I should mention it though, as it might be a factor for someone else.
Date published: 2011-07-24
Rated 5 out of 5 by from Keeps the bag clean, adds warmth Bought two of these before we went on a month long road trip with 2/3 of the nights sleeping in this liner and a sleeping bag. The liner is very soft and comfortable and helped keep the bags clean! It's much easier to just toss the liner in the wash than the bag itself, so we could launder them in the middle of the long trip if they became stinky.
Date published: 2013-10-25
Rated 5 out of 5 by from Does what it's supposed to We bought this liner for my down mummy bag, with the primary purpose of keeping the bag clean. As an added bonus, it also adds a couple of degrees to the bag's warmth. When the weather was too warm to be zipped in the down bag, the liner was the perfect lightweight blanket. It washed well after use, and seems to be good to go for the next trip. The material is a little thin, so I'm not sure how it will hold up over time, but so far, I'm very happy with it.
Date published: 2013-10-05
Rated 5 out of 5 by from Many Uses at a Price I Can Handle Bought two of these liners a year ago for an Alaskan backpacking trip in August. I live in a warm climate, so I hated to spend big bucks on a liner that I would not use very much outside of my trip to Alaska. I have actually found it to be very useful close to home as well as on trips. The liner can be hard to get into but that is just how all of these are designed. I found if I crawl into it and pull it up to about my waist, then slide into my sleeping bag and wiggle down it works pretty good. I found I can easily slide out in the middle of the night and leave the liner in the bag and crawl back in after I'm back in the tent. It is a little "slinky" feeling but I didn't feel like I slid around in it too much. It did increase the warmth in my bag by about 8 degrees maybe. I didn't get cold in a summer type bag in Alaska in August at a higher elevation even on a rainy night in the back country while using this liner. I was in a tent and not sleeping outside. What I really like about this liner is that when I have to cover myself in bug spray, I'm not worried about getting it all over my nice sleeping bag when I am unable to shower in the back country, this is a huge bonus for me. My son is also able to use this liner on his Boy Scout camp outs. It is a HUGE help that I can wash this liner after every grungy, showerless adventure he has with his Troop without having to go to the washateria to wash his sleeping bag. He even brings this liner on many summer camp outs, just this liner with a sleep pad and leaves the sleeping bag at home since it is very warm where we live. When he gets home, I just toss the liner in the washing machine and am done. All in all I like this liner, it was not the most expensive and serves the purpose of making my bag a little warmer and making it easier to keep my bag clean or even not have to use my bag at all on hot camp outs. I feel, since I'm not camping in frigid weather, this liner works perfectly for my needs and well worth my money.
Date published: 2014-09-02
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does this have a zipper to make it a double?

Asked by: ExiledMainer
The CoolMax Mummy Liner does not have a zipper so two cannot be zipped together.
Answered by: REIservice
Date published: 2017-01-17
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