ThreeLeaf Rechargeable Hand Warmer 7800mAh Electronic Portable Instant Heating/USB Back-up Power Back Battery for Samsung.iPhone

This hand warmer recharges faster and last longer than any other I've bought. Price was a big factor in the first two brands i tried. One of these, the Hot Pod ( https://smile.amazon.com/HotPod-Rechargeable-Pocket-Warmer-Sleeve/dp/B00I4OFGZ8/ref=redir_mobile_desktop?_encoding=UTF8&psc=1&ref=ppx_pop_dt_b_pd_title ) was, at the time, the least expensive. It was not a good product, lasting only about an hour. I never use it. The next one i bought, Baisidai, ( https://smile.amazon.com/Baisidai-5000Mah-Portable-Electric-Rechargeable/dp/B01MYNLG0Q/ref=redir_mobile_desktop?_encoding=UTF8&ref=ppx_pop_dt_b_pd_title&th=1 ) was a big improvement and I ended up buying several. However, they only last a maximum of three hours - at the lowest setting - and take 6 -10 hours to recharge. I then tried the Pisen (https://smile.amazon.com/PISEN-Rechargeable-Double-Side-Handwarmer-Gift-Giving/dp/B06XP2BDTY/ref=redir_mobile_desktop?_encoding=UTF8&psc=1&ref=ppx_pop_dt_b_pd_title ) which lasts a good 6-8 hours and has an automatic shut- off. It needs to charge overnight, so I'm not certain of the exact time, but approximately 8 hours. It was more than twice the price of the Baisidai but a comparatively good value. However, it heats very slowly and has only one heat setting. It is also awkwardly shaped and too large for my hand to hold comfortably.Then I found this one! Two days after I bought it, I ordered another. It heats quickly, lasts a long time, recharges quickly and, in spite of the larger size is comfortable to hold. It's less expensive than the Pisen as well. It actually lives up to the description and I highly recommend it.

These warmers have been great so far for me, and if anything changes I will update my review to reflect that. My use case is completely different that the majority of people who will buy these warmers/power banks. I live in a very cold area. Its the middle of November, and it was between 10-25 degrees all day long yesterday. On top of that, I work at a high security facility and am strictly forbidden to bring my phone inside. I also work as a nurse, and we are chronically short staffed. Because of this, it is a very regular occurrence for my phone to have to sit in my car in freezing temps for 16-17 hours at a time. I was tired of having the temps kill my battery, not to mention putting undue stress on an expensive piece of hardware that I want to last a few years if possible. These hand warmers are the perfect solution. I purchased 2 of them to try to give myself enough coverage for the entire 17 hour work day. I am using these inside an insulated canister that I had left over from an old Zojirushi bento set that I have not used in a few years. I just stuff them all inside, turn one on, and it keeps my phone warm enough where I don't have any battery drain and the power button still feels clicky instead of the solid, immovable mess it would be before. It doesn't make my phone hot to the touch, more like room temp, which is exactly what I was looking for. I was concerned that there was potential for condensation to build up inside the sealed canister and do more damage to my phone, but I have not noticed any moisture at all. Just incase, and to add a little more insulation, I just wrap the warmer and my phone in separate washcloths. Couldn't be easier. I keep the second one inside of the canister as well in the included felt bag, just so it doesn't have to be exposed to the cold. Yesterday, with temps from 10-25 degrees, I turned the first one on and it ran continuously for 8 hours on the lowest setting with no issues. I am not sure how much battery was left, but there was still one light that would turn on to indicate charge, so I guess between 1-33%??? If I had to guess, I would say it was probably about 10% leftover. Then, in between shifts, I just swapped the one in the bag with the one in the washcloth. The second one had pretty much the exact same output as the first. So these give me the coverage that I need to keep my phone at the perfect temp for my entire ridiculously long work day. The real test will be if I can get the same results in January when it is regularly below 0 degrees for the entire day. Only time will tell, but if I don't update this review assume that it is working well. If I had to have a negative to say about these warmers, it would be that they do seem to charge a bit slow. However, I was using an old charging plug that came with super cheap 7 year old LG phones (not smart phones, just garbage). With these chargers it took about 5 hours to top off the warmers, but since that is about as long as I have at home between these shifts it should suit my needs. I am going to look into cheap quick chargers and see if they help with the speed though, just to be safe. I can not speak to how well they work as power banks, as this is not my intended use and they will never be used like that. I really hope these things last...

The exterior craftsmanship is excellent. I cannot predict if this item will last a long time. It took a full charge in about 5 hours. When I unplugged it and turned it on, it warmed in seconds. If it lasts, this will make my workplace much more bearable during the winter. Follow-up-- I decided to give it a try this last few weeks at the end of summer. At my work, the air conditioner dumps all of the cold air for the building above my desk. While everyone else swelters on summer days, I'm freezing. I put one of these in my back pants pocket, and one in my shirt pocket, and I'm warm enough to work in comfort. Also, I prefer this particular unit for two reasons: 1 The battery is bigger than most, and 2 The on/off button is flush so it is less likely to be pressed accidentally.

I bought 2 of these for my son for Christmas. Not even a month later, he is afraid to use one of them because it melted. He is worried that battery acid will leak out. The other unit is still working fine, so I averaged the stars to reflect 50% satisfaction with my purchase.

Bought in February 2018 and died October 2018. Mainly used the device for a heater so I'm not sure how well the charger function works. I kept it in my back pack and used it at work about a couple times a month. The three heat settings was nice. The lowest setting was already warm enough for me most of the time.

The hand warmer is nice and hot but fails in durability. The aluminum shell is prone to denting and has started to separate from the body. I can probably fix this with a bit of glue. Also the indicator lights bleed into one another. No big but a bit irritating. I have a larger 10000 mah hand warmer i purchased here on Amazon that is much more durable.

I bought this for a friend and she reported that it works great. It charges her phone in a hurry and the hand warmer puts out lots of heat.

I'm using this for hand warming while hunting. I'm also using it during cold mornings. This warms up quickly. It keeps a charge for a long time.