Having noted the low overall ratings of other heat mats compared with Spider Farmer, I gave this unit a try. I am using the paper towel method to germinate hot peppers. The controller was set to 82F, and the sensor placed between zip loc bags containing the seeds. Adjacent to the sensor was a hand-calibrated reference thermometer previously used to do quality assurance monitoring in a medical lab. There is a slight delay in the sensor readings, but at the top and bottom of the temperature range the Spider Farmer was off by less than one half of one degree compared to the reference. That is pretty hard to beat for a product in this price range! A second lab thermometer displayed a full degree below the reference. Yes, I am happy and would suggest this product to anyone using seedling heat pads. It also worked with an older heat pad purchased years ago from a seed company.