Temp Rating
Insulation Type
| Shape | Mummy |
|---|---|
| Packed Size | 9.8" x 3.5" x 5.5" / 25 x 9 x 14 cm |
| Weight | Compact: 13.8 oz ; Standard: 14.8 oz |
| Shell Fabric | Thermolite® EcoMade polyester |
| Length | Compact: 78 in. ; Standard: 85 in. |
REVIEWS
28 Reviews
Emily S.
[This review was collected as part of a promotion.] Kept me very warm in Yellowstone including a night that dipped to 27F
Raymond N.
[This review was collected as part of a promotion.] After watching several YouTube videos, I made the decision to purchase the fleece liner for my Sierra Designs 35° mummy bag. I was able to remove a layer of clothing and slept warmer in the bag utilizing the Reactor. Awesome product from Sea to Summit, I highly recommend.
Ivan A.
Great liner it is super soft and comfortable and adds plenty of warmth on cold nights.
Megan W.
I haven’t had a lot of experience with this liner yet but what I mainly got this heavier fleece liner for was to actually use it for desert weather (like in the summer in southern Utah) when my sleeping bag would likely be way too hot… I figured I can always sleep on top of my mat and use the liner for a light cover in the summer months. I think it will be perfect! And obviously it will come in handy for cold weather when I need just a bit more warmth along with my sleeping bag.
Ivan A.
[This review was collected as part of a promotion.] Have taken the Reactor Fleece Sleeping Bag Liner on a camping and on a backpacking trip now. Both times it worked great keeping me warm and felt very smooth and comfortable. It got down to the low 30's at night in the desert and I was very comfortable.
Cheri P.
[This review was collected as part of a promotion.] My grandson loves it! He's excited to use it on his next Boy Scout outing. I will be buying another one for his younger brother too.
Hagen J.
[This review was collected as part of a promotion.] Easy to clean and very comfortable and breathable. Would recommend
Tom K.
[This review was collected as part of a promotion.] Hard to get into but should be warm. Probably should have got the one with no zippers
Alice E.
[This review was collected as part of a promotion.] I got this to add some degrees to my 15 degree sleeping bag for my outdoor camping experience in the Boundary Water in northern Minnesota in January. We were lucky in that it never got below 0 degrees but so glad I had it just in case it was needed. It did help in providing some extra security when my bag got a little wet from a leaking hot water bottle. I like that I have flexibility in keeping my feet bundled or kick them out. Very soft material. Used it with my Nemo spoon style sleeping bag.
Zach Z.
[This review was collected as part of a promotion.] Definitely keeps me a little warmer on those chilly nights and great so I’m not getting all my sweat and dirt inside of my sleeping bag. Very easy to wash and light to carry in my pack. Will definitely purchase again.
Don L.
[This review was collected as part of a promotion.] Very roomy and comfortable as expected. My only concern is using it with my air pad. Why would S2S use a sharp metal pull tab on zipper instead of fabric or pull cord. I rolled over and noticed the metal tab jabbing into my air pad. Thankfully I noticed and placed a piece of luko tape over metal tab. Will probably return or use it with closed cell pad.
Cameron L.
[This review was collected as part of a promotion.] I have had other liners, but this is the first one that you can wear outside of the sleeping bag because of the foot well opening and it will stay on you because of the arm openings. It’s especially important on cold mornings to have this option. Now it’s not a perfect fit when you’re wearing it out of the bag it will hang down requiring you to fold it up. Something like a bathrobe that is too long. But it is no bother. I have used it a couple times now and I would estimate you get half of an R value point extra in insulation. I’m happy with this liner and will be using it on my cold paddling camping trips.
Brian T.
[This review was collected as part of a promotion.] I used this as my main sleeping "bag" on the Camino de Santiago, and it was perfect. Smaller and lighter than a full bag, but still plenty warm in the hostels and albergues along the Camino. Recommend.
Quyen T.
[This review was collected as part of a promotion.] Worked really well for me in temperatures below freezing. I also appreciate that the material is soft against my skin. My sleeping bag has a foot zipper, which I am glad I was also able to use with this liner.
Penelope P.
[This review was collected as part of a promotion.] Only used it at home for one night. Because I am a side sleeper. Would love to have center zipper a little longer and only one zipper. The market lacks items for side sleepers. Otherwise no issues. But this should work as a dress when I do laundry as well
Read All Reviews (28)
*Online only. First-time subscribers only. Returning subscribers will be resubscribed for marketing/promo emails.

*Online only. First-time subscribers only. Returning subscribers will be resubscribed for marketing/promo emails.
© 2026 Public Lands
If you are using a screen reader or other assistive technology and are having problems using this website, or if you have any other difficulties accessing this website, please call 1-844-890-0896 for assistance
*Donations are based on purchase price, excluding taxes or other charges. The Public Lands Fund is a program of the DICK’S Sporting Goods Foundation, a 501(c)(3) charity. Learn more at publiclandsfund.org.