Relief PakHot Button Instant Reusable Hot Compress, Neck

I bought it for back pain. The shape of it is good and it stays on shoulders. That's about it, do not recommend to buy! It gets hot quickly but does not stay hot for long enough! after 20 min it becomes warm where you can feel it only directly on the skin. After 30 min from the time heated, it no longer warm!!! Did not return to original form after boiling in water.

I love these. Not only are they great heat packs, they are great for science demonstrations (I use them in my science class too). It is not a chemical reaction, but a physical change. The solution inside actually "freezes" at 130 F but it is super stable, super saturated solution that requires some activation energy to start the crystallization. The purpose of wrapping in a towel when boiling is to prevent the plastic from touching the metal pot directly and melting. You have to melt all the crystals (even microscopic ones) to reset the fluid, or the crystallization will start again as soon as it cools to 130 F.

These seem to get pretty weak about a month down the road until there is no heat after you boil them. But to be fair I do use them really often, almost daily. I have had other brands that have lasted years when compared to this same amount of usage

Worked great the first time. After following directions and boiling to “reset” everything seemed to be working well. Then after 15-20 min it solidifies on its own again but this time with out heat. Also, Amazon says it’s not eligible for a return. Save your money. Buy from a different manufacturer

Horrible!!! No gasten su dinero en esto. Dice que se puede devolver y cuando lo compras y te das cuenta que solo funcionó una sola vez y vas a devolverlo te dice que no se devuelve no se como @Amazon permite esto

It came and it was busted and just ruined the packaging was totally damaged too!

I use these many times a week. Ive purchased a few throughout years & these seem to be upgraded. I like the quality & also the fact that it goes back to liquid state faster

Does nothing when you click the button. Also I was NOT able to return item because apparently it is "non-returnable".