Heated Sleeping Bag Liner,Travel and Camping Sheet, Pocket-Size, Lightweight, 100% Cotton Flannel Fabric, Special Metal Heating Plate with Maximum Power 9W, USB Interface

I'd rate it 3 1/2 if I could. It'd be a 4 if it was a little longer.I've only tested it once so far. The temperature dropped to 27F, but I was able to sleep comfortably. I found the heating elements work surprisingly well. The heating element on the torso area seems the warmest, but it could be due to better body contact compared to the legs. A mummy bag shape to the liner would help. I tested it in a rectangular sleeping bag so using it in a mummy bag would also help.The temperature dropped to 27 F, yet I stayed warm enough to sleep comfortably. My 10000 mAh battery pack lasted the whole night also. I had enough power left in my battery pack to go a second night.Overall, I am pleased. It does need to be a little longer. I'm 5'11" and isn't quite long enough for me. I am also happy my battery pack should be large enough to last two nights. I could likely get the the same effect using disposable chemical warming packs. I am amazed this works as well as it does using a 10000 mAh battery pack. I'll be sure and edit my review after I've had more opportunities to test it.

For what it is - a heated liner - works great. I knew I wasn’t going to get the heat levels I get with my home heating pad but I needed a usb charged heat source. I used this with my 10000amp anker power bank and I get 4-7 hrs out of one full charge just as advertised depending on the setting I choose. I wrapped myself in this around the campfire at around 50 degrees and it took the edge off in the cold and also used it to lay on underneath me on my air mattress in 35 degree weather in big bear and it helped with the cold. This is an unbiased not paid for review. It’s not a hot heating blanket - it’s a warm liner and works well enough for me. I’d recommend it for that purpose. I didn’t want to spend 100 bucks on a heating blanket for camping so this was a better alternative for me.

I have raynaud's but live to camp in the Pacific Northwest where the nights get pretty darn cold. I bought two decent size charging cells and just plugged it in. The only downside is the placement of the pocket for the power cell and that you're supposed to sleep on top of the heated part. I kept rolling on top of the power cell which wasn't too comfortable. Other than that, it's super warm and make the cold nights very comfortable.

Used with a 50000 mAh solar power bank for a recent camping trip. Takes about 5 mins to warm up but then heats you to the core. It snowed on a trip where it was supposed to be low 50°s and I was toasty.

Missed my return window by 2 days and am super bummed, as I bought 2 of these. Took on a 3-week Overlanding trip and could only get 1 to work and the 1 that did work didn't heat well at all. Ended up using my heated vest in place of these to stay warm on cold nights. These liners are a GIANT waste of money.

It heated up fine but zipped on opposite side of sleeping bag. Was very difficult to get in and out. Also very slick in sleeping bag making it twist all around throughout the night.

Used for first time camping, tenps dropped to 50 and I was so excited for it. Once turned on heated maybe an inch of the bag and stopped just a few monutes later. HUGE disappointment. Do NOT waste your money.

I got two of theses one for my father and one for my sister who live up where there is no natural gas. The electric went out a few times because of winter storms, they were happy to get them.

This Very thin bag liner has the controls under your shoulder. As soon as you move you changes the settings. It also Eats the battery very quickly. I have a large battery pack and it only lasted a few hours ( heat setting irrelevant as you sleep on the control)

Battery packs wont keep this going for long, I get super cold sleeping and was in a -0 C bag. This was just a waste of space. Hard to get into, and not very warm anyways. I would buy a good pad or good sleeping bag liner with the money from this.

pretty warm when you set it on high, I wish they will produce one with the heating element on the top also, so both top and bottom element would wrap you up and you'll feel toasty during the cold time.