Plug it in and forget it. Used under my mini-greenhouses or under seed trays you just plug them in and forget them. They maintain a good soil temperature for germination and early growth and seem to be water-resistant when you make a mistake, as we all do. Coupled with my Sun Blaster lights (also reliable) I can get good vigorous seedlings even though I have no greenhouse, just a woodwork shop with skylights.

Fermwarps and other heating elements have been hard to come by thanks to increasing interest in homebrewing due to COVID-19. Got one of these in pinch to use on a 14 conical. Works like a dream! Brought the temp of 11.5 gallons of soon to beer up to desired temp in about 8 hours, maintained that temp once it was reached.

Sure it works great for seed starting too!