Heat Press Platen Wrap Cover 16X20 Inch, Non-Stick Heat Resistant Teflon Protect

You can use it for both the upper / lower heat transfer plate. For the upper platen, it protects the upper platen from scratches, sticking residue, inks, and other adhesives; for the lower platen, it will protect the silicone pad on your lower platen from scratches, wearing and tearing.

eBay