As someone who struggles with occasional excruciating cramps and painful periods frequently, I don’t want to have to take painkillers all the time and I can’t walk around in public with hot water bottles strapped to me so this product has genuinely changed the game! They stay hot at a consistent heat for 12 hours + it isn't burning hot but soothing and even if you take it off for a few hours and want to come back to it, it will still be hot. They sit discreetly under clothing and enable me to go about my day comfortably when I otherwise couldn’t. The other great thing is they are completely chemical free they are a naturally heating product with no side effects (unless you applied it directly to your skin which you shouldn’t) the only criticisms I could give the product is too improve the stickiness especially if you are walking around all day it can dislodge occasionally which is annoying and perhaps making a black coloured option so it’s a little more discrete? Another idea would be to make the packets they arrive in (inside the box) a little smaller closer to the size of the actual heat pad to store in handbags easier? And in future development if there was a way to get cooling patches for summer days. But overall I can’t thank Wuka enough for developing this product it has impacted my life significantly and I feel confident to go places during my period when I otherwise wouldn’t because of painful cramps. Would recommend to any women I know.