Sea to Summit  Thermolite Reactor Sleeping Bag Liner

I purchased this to give me some extra warmth (I run cold) in Patagonia, and I am so glad I did! First, I was surprised by how thin and soft it is. Really soft. I used it a few times while hanging out on the couch at home, and it truly does keep you warm. If it's really cold, you need to cinch it up properly (I rarely did) and you'll be roasting in no time. I ended up taking it on the long flights with me, and using it as an airplane blanket. Frankly, I also planned to use it as a shawl if I needed it while hanging out in the evenings. It's amazing. I'm not putting it away with the camping gear, I'm keeping it handy as a spare blanket at night to go star gazing!

I bought this at the members sale and found out later you can fit an entire Nemo tensor long wide inside it and synch it up so it doesn’t come off! Now I won’t have to sleep directly on the pad when it’s hot out and dirty it up and the liner is also softer than the pad material! Does not look like it puts a strain on stretching the foot box, still within the elastic region of strain. Originally bought it to add some warmth to my 20 degree sleeping bag and as something I can wash without dirtying my bag. Have not used sleeping yet, but will soon in April. Double whammy!!

I join the ranks of satisfied reviewers. Writing this review on behalf of my sister... we trekked for 3 months in a Himalayan winter that spilled into summer. Since I joined the trek late and had heard my sister was struggling with the cold, I brought her this liner to warm up her sleeping bag. I haven't seen her so in love with a fabric since her childhood blankie. She even opted to use it once we returned to town and checked into a guesthouse. I was skeptical to buy this at first because of the price, but seriously, what's in this thing? Magic? Worth the dough if you're into cozy factor.

I bought this bag for several reasons, but primarly for a lightweight and warm weather bag. I'm in NC and do most camping in NC and it's warm here most of the year. I bought this bag/liner and have so far only used it alone. And that's what I wanted it for. It's cozy to sleep in and just right for warm weather camping. In "cool" weather, I've used it with a space blanket over it and was fine too. I haven't yet tried as a bag liner, but based on its solo performace I'm sure it will add a few deg of warmth to my mummy bag. I also keep it in a survival pack in my trunk when not camping.

I have only good things to say about this liner! I'm a small girl who gets cold easily and this is a wonderful item to own if you camp or travel. It only weighs a few ounces, is easily stashed in its own little stuff sack, and has so many uses. I've actually pulled it out on international flights (like I said, I'm always cold) and I've used it in my bed when staying in hostels or hotels with questionable cleanliness. It was perfect when backpacking in Japan where temps reached 110 - something to cover myself but not get overheated. Washing/drying is a breeze, too. Highly recommended!

I sleep cold like most women. This liner makes my cheap summer mummy bag work in shoulder season, and will make my new 0 degree bag a true winter option. In the past 8 years, I've used this as a liner in down to 0 degree weather with a rental bag, with my husband's borrowed 0 degree bag, and with my own bag. It's soft, comfortable, breathes, warms, and works fine with or without socks and layers. I've used it in hostels and guesthouses. I've also used it summer camping on its own. I machine wash it, air dry, and it is the same as when I got it. I asked for it one holiday and it's still one of the better things I listed!

I recently took a trip to Yellowstone and did some backcountry camping. The temperatures got down to the mid/low thirties overnight and I knew from previous (and uncomfortable) experience that my sleeping bag wouldn't keep me warm enough. I purchased this liner to supplement my sleeping bag and it totally worth the money. It's very thin and lightweight so I was concerned about its effectiveness, but I was incredibly comfortable and warm all night. The fabric is also very soft and cozy and added minimal weight to my pack.

i've only had one opportunity to use this since i just purchased it, but so far, so good. we camped in 20 degree weather and my husband had to shed his after getting too warm (we also have 0 degree bags, but they are ~15 years old) so i doubled up and had the best camp sleep ever. he would likely leave a less glowing review since he is a human radiator and also like to turn cartwheels in his sleep and found the liner a bit too confining. typically, we zip our bags together which gives him a bit more room to kick me in his sleep, however, since these are super light, there are no zippers to combine them so he was additionally confined to his own sleeping bag (probably another reason i slept so good!). short story long - i loved the liner, but he would probably have a different story.

Bought this to extend my 20° rated bag. It worked amazingly well. I was toasty warm in 10° weather.

Brought this just in case for my first outing of the year this April, Herman Creek in the Gorge. Still pretty cold at night and snow at 3200 ft. I have a 20 degree bag and I was at the edge of being cold the first night at a lower elevation, but managed to stay warm. The second night was a bit higher and colder and I was having trouble falling asleep so I broke out the Thermolite bag liner. It's pretty thin, didn't really think it would do much but it did. It took the edge off, I warmed right up and fell fast asleep. In my opinion it's a great way to ad versatility and warmth to your sleep system without having to purchase another sleeping bag. Glad I had it with me. By the way, get in the liner first and then slide into your sleeping bag. This technique seemed to work well.