Bathmat With No Suction Cups What Product Can Be Safely Used As A Non Slip Surface Without Damaging The Surface Of A Reglazed Bathtub?

What product can be safely used as a non slip surface without damaging the surface of a reglazed bathtub? - bathmat with no suction cups

I can not use a vacuum or adhesive pad on the tread stickers. Anyone can make acrylic coating melt surface.