Heat Wave3x5 Reusable Click Instant Heat Hand Warmer (Small Green 4 Pack)

Works well and appears well-made. Puts out just enough heat to warm up hands comfortably, and lasts an hour or so. Handy, safe, and also a neat demonstration of the physics of heat and phase change.

Nice quality, but the heat does not last very long. Useful for spot warming of stiff joints.

I probably will not buy it again. Lasted 1/2 hour

These warmers have been around for a long time, I used to have them in various sizes and shapes...... I loved them. But like everything as they aged, and I'm talking 20 years time, they stopped working the same. Recently I had need for a small sized warmer for my eye lid and searched on Amazon for something to fit the need. Much to my surprise the Heat Wave warmers were in the search results and boy was I happy to find them again. An even better surprise is that they work exactly the same (the outer plastic is now green, used to be clear) as they used to with the improved band around the metal starter mechanism. But they are indeed the same product I owned 30 years ago and still work just as well. I am so happy to have found them and glad I ordered them! They work really well!

To clear up some confusion:The heat lasts about an hour if you leave them out in the cold air. If you want a longer duration, keep them in your pockets or something. They're too big to fit in mittens, but if you have a couple of these in your pockets you won't even need mittens.If the heat is only lasting 30 minutes, you probably didn't follow the instructions. After activating the pack you're supposed to squeeze and massage them until they are soft and malleable. This makes them more comfortable and makes them stay ho for longer.You need to boil them for about 15-20 minutes as per the instructions on the pack. That means about 5-10 minutes to get the water boiling and another 15-20 for all the crystals to dissolve. I just toss them in cold water and set a timer for 30 minutes. It's really easy.Compared to other similar products, these are very high quality. They are a great size both for use and to fit in a pot when you boil them. The pack is hearty and you don't have to take special precautions when boiling them. Other brands need to be wrapped in cloth or they will become damaged when touching the bottom of the pot. Other brands will also go off accidentally if you bump them too hard, but these seem to be well designed and only go off when you press the button.I got these for my wife, and her family was so impressed that I'm ending up ordering another pack to give as gifts.

I always loved using these but came to realize they only stay warm for about 20 minutes or close to 30 if you keep it moving.Great hot heat which is better that the disposable but the disposable can stay hot up to an hour I mostly experienced

I ordered these for my husband who suffers with the cold. The first one he tried, failed to activate but the next worked well. I'll update when he's tried the others.

I have raynaud's disease and my fingers turn blue and start going numb, even during the summer. I bought these because I need the heat to help the circulation and to get the feeling back. I love that they are reusable. It is very easy to activate and to deactivate them. I will probably buy more because even my kiddos like using them.

I had another brand of the same type of product and I think that it stayed warm a bit longer than this one, but they generally work the same. Liquid becomes warm and thickens after little metal disc is bent inside. Gets VERY hot, nice to warm up hands and pockets in the winter. When they are hard, cold, and useless, just boil them until they are liquid again and they will stay liquid until the metal disc is bent inside and you can repeat the pocket warming process. Always store them liquid. Do not store them in the hardened state after use for too long. Also, don't be afraid of the price. I used my last ones for a good year or two constantly before one stopped working. This is far better than disposable ones.

found them a little bulky

they literally stay warm for 10 min. they start to crystallize again immediately even after boiling them for 30 min. not useful at all.

So so , not that great product no more next time.

In open air they run for about 20 mins which makes sense since they take about 20 mins to recharge. Was simple to reset it after use and they get decently warm.They would last longer if you insulated them (wrap in towel or clothing/etc). Kinda wish they ran a bit longer though.