I really almost bought one 2 times.
But the need for a plastic piece underneath the seam????¿?
How hot is that devil???
Kool-Glide is good for sections or door seams where pulling a gooey iron out from under the carpet can get messy. Regular iron is faster, and you can get better (or cheaper) tape.
I've always used the Kool Glide tape right on top of the carpet pad. Been doing it like that for over 15 years.