Sea to Summit Reactor Fleece Mummy Sleeping Bag Liner

About This Item

Temp Rating

15 to 30 Degrees

Insulation Type

Synthetic

Design and Details:

  • Traps insulating air to increase warmth of a sleeping bag by up to 14°f /8°c
  • Stretchy, thermolite® fabric is incredibly comfortable
  • Lighter weight and more packable than fleece
  • Technical mummy-shape with drawstring hood
  • Easy care - machine wash with no special soap is needed. avoid fabric softeners and dryer sheets
  • Keeps sleeping bag clean
  • Packs into its own ultra-sil stuff sack

Specs:

  • Weight: 8.7 oz | 248 g
  • Length: 6 ft 10" | 208 cm
  • Packed size: 5.75 x 4" | 15 x 11 cm
  • Brand : Sea to Summit
  • Country of Origin : Imported
  • Web ID: 23S2SARCTRFSLPNGBCSL
  • SKU: 25757206
ShapeMummy
Packed Size9.8" x 3.5" x 5.5" / 25 x 9 x 14 cm
WeightCompact: 13.8 oz ; Standard: 14.8 oz
Shell FabricThermolite® EcoMade polyester
LengthCompact: 78 in. ; Standard: 85 in.

REVIEWS

4.9

27 Reviews

Received incentive

Old Reactor Warmth

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.

Super Happy With This Liner!!

Great liner it is super soft and comfortable and adds plenty of warmth on cold nights.

Great So Far

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.

Received incentive

Have Taken The Reactor Fleece

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.

Received incentive

Reactor Fleece Sleeping Bag Liner

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.

Received incentive

Noticable Warmth

Easy to clean and very comfortable and breathable. Would recommend

Received incentive

Very Difficult To Get Into

Hard to get into but should be warm. Probably should have got the one with no zippers

Received incentive

Offers Flexibility

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.

Received incentive

Definitely Keeps Me A Little

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.

Received incentive

S2s Reactor Extreme

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.

Received incentive

Sleeping Bag Liner You Can Wear

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.

Received incentive

The Perfect Camino De Santiago "Bag"

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.

Received incentive

Great For Winter

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.

Received incentive

Side Sleeper

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

Received incentive

We Survived -10°f In New Hampshire: Sea To Summit Fleece Liner Kept Us Warm!

Our Boy Scouts of America troop braved the annual Klondike adventure in New Hampshire, facing temperatures as low as -10°F. Proper layering and quality gear were essential, and the Sea to Summit fleece liner proved to be a game-changer. Combined with a 15°F sleeping bag and a thermal liner, the fleece liner added a noticeable boost in warmth and comfort. It effectively trapped heat, prevented cold spots, and made a significant difference in overall insulation. The soft fleece material was cozy, and despite the extreme conditions, we woke up warm and well-rested. Highly recommend this for anyone looking to enhance their sleeping system in cold-weather camping.

Read All Reviews (27)