Review on 2 Pack NAMOTEK Plant Heat Mat - 10X20.75" Durable Waterproof Seed Germination Heating Pad MET Standard by Melissa Merkel

I'm not sure if they're made in Japan, but the writing on the mats is Japanese, which in my experience with electronics indicates a higher quality product. These are much nicer than my other heat mats. The plastic is thicker, the heat more uniform, and they unrolled and flattened out nicely. To flatten out, I put it on top of my metal washing machine, plugged it in, and after it started to heat up, sat two 9x13 cookie sheets on top with something to weigh them down. After about 30 minutes I unplugged the mat and left it there overnight. No wrinkles or curling whatsoever. I've had both of them going under seedlings for a week with no problems; they're on an unheated porch, so they're pretty much on all the time, one is on a thermostat and one is not. I'm very happy with them.