Tropicallvr

That's the type i use, both those links have good prices. They seem to have "hot spots" on them though. I usally have 5 chunks(inch or less thick) of styrofoam between the mats and the trays so that it heats more even and it stays cooler(can get well over 100F if directly on mat, and cook seeds)



Forgot to say on this post that i use the one that is big enough to hold 4 trays, so it might get alot hotter than the smaller ones.