you should look into Ultratherm UTHs from RBI. they're not adhesive and you adhere them to the enclosure with aluminum tape. all my snakes have Ultratherm UTHs and i like that i can remove and reapply them whenever i need to.
Just an FYI....... You can do that with any heat mat.
Remove the wax paper, apply foil tape to the sticky side of the mat (glue to glue) and now the adhesive is covered and you would then use foil tape around the edges to stick it to whatever.....