ANTOGOO Cool-Sun Wireless Earbud, Coolsun Bluetooth Headphone, Mini in-Ear Headset Sports Earphone with Mic for All Smartphones

Another Raynaud's Syndrome person here, ugh. What an annoying condition. My fingers can go from warm and pink to ice cold, white, and numb in a matter of 5-10 seconds in the winter - even just getting ice cubes out of the freezer. Needless to say, I've been through a lot of hand warming products over the years, everything from down mittens to chemical hand warmers, etc.I really, really like the USB rechargeable batter hand warmers in general, and of them (I've owned 6) this is one of my favorites.Pros (relative to other USB hand warmers only):- the heat is very strong - blistering, actually, if it's fully heated up and you're just grabbing it. I haven't temperature tested it with a thermometer or anything, but I can tell you that if most of them get "hot but not very hot", this one is super-hot. In fact, so hot it can be hard to hold, which is mostly a good thing, because you can always let go of it for a minute if it's too hot, but you can't make it hotter if it just ain't hot enough. I have not encountered any other USB hand warmer that puts out this much perceived heat. Seriously, you could probably cook an egg or a grill cheese sandwich on this thing.- auto shut off is a handy feature. Seems to go off automatically after an hour. Really like this feature- the battery is bigger than some of the others (though not all of them) - 7500mAh vs typically 4400ish. And this is a case where bigger is better. Bigger batteries last longer, obviously. This pumps out its ridiculous amount of heat for a good, solid 2.5 - 3 hours, compared to the 45 mins - 1.5 hrs of some others. By the way, don't believe the claims either of this or any other USB hand warmer. NONE of them last the advertised 6-8 hours, period. Trust me, I have been around the block with these devices and those claims are ridiculous. Getting a solid 2+ hours of heat out of one of these is victory, and this one delivers. Don't be surprised if you buy one of the 3600-4400mAh models and get 45 minutes of heat, that's just how it is. Also, if you're going to use it for back-up phone charging, you're not going to charge a phone effectively with 3600-4400mAh; you really need this (or comparably large battery) to do that.- though a bit larger or thicker than some of the others, it's actually a very comfortable, ergonomic shape for wrapping your whole hand around and getting all five fingers on the heat. Don't be seduced by those little ones that look like they're just slide right into your pocket and be out of the way!! They do in fact do that, but they don't have either the large heating surface or the longevity of this unit. A large heating surface is very important with these things. The part making contact with your skin loses its perceived heat in a minute or two; only the part you're not touching stays scorching hot. With such a large 2-sided heated area on this unit, just turning it over in your hand will exposed your palm and fingers to a fresh section that will be very, very hot. Meanwhile, the "used up" cooled-off parts you were holding before will go back to blisteringly hot in about 30 seconds. Not many (or any) other hand warmers have this much surface area and can constantly give you "virgin" areas to apply high heat to your hand continuously.Con:- Quite unusually for this type of product, it has no "low vs high" switch. When you turn it on, you're getting the full blast of heat. It's odd that it doesn't have this functionality since almost all of them do. Not really a big deal, but to be clear this one pumps out a LOT of heat and it can in fact get too hot, so hot you have to remove your hand, whereas with most others you can just kick it down to the "low" setting. This unit with a hi/lo switch would definitely be my favorite device in its category, but unfortunately that is not offered (yet).Given its high heat level and lack of option to tamp down the heat level with a hi/lo switch, it's suited mainly to outdoor use in the winter, where its high heat and large heated surface area provide distinct competitive advantages. For indoor use only, I might recommend one with a hi-low switch, really any of the ones with 7500+mAh would be suitable for that purpose. I do use it indoors but sometimes it does seem too hot to me and I have to turn it off and give my hands a break for a while.On the upside, one thing people complain about with USB hand warmers is that they're not hot enough. Trust me, you'll never have that complaint with this model.I feel that in this product the manufacturer has what could potentially be the best USB hand warmer on the market, but it really needs a hi/lo switch. I'm still giving it 5 stars, because of its combination of ergonomics, high heat level, longevity, simplicity, etc. But it needs a hi/lo switch.

Update...I now have two of these. I love them. They get too hot for skin contact especially say on the wrists or behind knees where skin is thinner and more fragile. I like to use them there however as it warms the circulating blood to hands and feet depending on what's cold.I place them in clean socks to solve the problem their little sacks fall off. The directions at best tell you four hours and they stay on for one hour and auto off. You can turn them off earlier by pressing the tiny button on upper side and watch for the tiny light next to button to go out. If you run a full cycle it goes down 1/4 of a charge each time. I have never taken it down more than three cycles but most of the time I recharge after one cycle or two for both. I bought the second from Amazon via it's used/like new option for 17.00...but the price I'd paid for frist new one was 25 and now down to under 20. So I will use camping most of the time. I have a small 800 watt solar generator/inverter with one usb port, one 12Volt port and two AC outlets. So since I have charged up that over sized deep cell battery system...I've been charging all my power banks including these with the generator. They power up pretty fast to full charge. I also picked up a double adaptor for the 12V Cig port that allows me to have two more USB ports. Since I also intend to turn LED light bulbs with switches camping too. These little hand warmers should help keep me warm on a colder night in the sleeping bag in a tent. I am quite happy and with the sock system.....it's turned a good thing into even better.Below original review:Oh it did get pretty darn warm. I like it. Different and hope the heat continues to work and it works as a solid power bank. Time will tell on both. But for now it's interesting and yes it's summer who needs a hand warmer. How about a sleeping bag warmer? I'd like two but I already just bought two larger power banks for less than this little guy so...yeah..maybe later in the year. I'm going to try it out two or three times in the heat mode to see how it does. And then recharge it. If the price came down 5-10 dollars I'd definitely buy a few more as gifts too. If it holds up a couple of years it'll be a five star item but the jury is out and some folks say it fails pretty fast..heat wise. But I would reorder if it broke. The alternative round shaped one in pink and purplish is awful looking colors and not shapped nearly as nice.

This review is based on initial impression, as I have only used the handwarmer once for about 30 minutes -- I am hoping it performs as well for longer uses as it did for the first!! Overall, I am super happy with my new battery powered hand warmer!!I have used Zippo hand warmers for years, and they work great, but I have wanted to try a battery powered hand warmer. About a year ago, after looking at the battery powered options, I decided they were too expensive to gamble on, considering many of the reviews were not favorable. Well, I just saw this little SunJack handwarmer on Amazon, price was good, reviews were decent, so I decided to give it a try. I'm so happy I did, because this little thing is quite impressive -- it puts out great heat, definitely enough to keep a hand in a pocket warm. The indicator lights are great -- know what level the battery is, and that the hand warmer is on. Since I am going to be using this as a hand warmer and not a power bank (I have several other power banks), I think I will cover the USB port with gaffer tape to keep pocket lint/dust out of there.I can only find two negatives (and they are minor ones!!). The little loop in the side to attach it to the strap is very poor quality, and I don't think it would last long under the weight of the unit. I tried to use my micro USB to charge it, and it seems like their port is slightly off, not allowing my cord to be inserted, however, their cord inserted fine.