I own the 6"X 12" size. I'm reviewing this as a hot pad because I've never used it before cold. When I first got this I thought it was very cool and inventive because I had never heard of a heating pad that used clay. Originally when I was shopping, I was looking for a hot water bottle but I thought this product would be better. I also like that it could be strapped onto the body using the velcro strap. I've owned this about a year. I stopped using it for some time because it was kind of frustrating to use because it doesn't stay hot very long. Mine probably stay at a good temperature for about 30 minutes before I need to reheat it again. I have a 700W microwave so I microwave this for 1 minute and 20 seconds on high. To reheat it, you put it in for half as long. I think it gets too hot. Plus I think the clay gets hot spots because even though I smooth it so it's even, sometimes some areas are burning hot. The cloth cover of the pad also gets worn over time and starts to unattractively pill. I mainly use this for my lower back and abdomen. Lately I've been using it with a castor oil pack. The thing is it doesn't really stay hot long enough. I'm looking for another alternative. If you do buy this, opt for the larger size even though it's harder to find.