Strong suction cup design works on any non-porous, flat surface, including smooth tiles, glass, porcelain or fiberglass. The grab bar will not harm surfaces when installing and used properlyTextured, contoured rubber provides a comfortable non-slip grip, won't slip even when wet providing safety and security in the bathroom, tub, shower and toilet handrail, perfect for the injured, elderly and toddlersThe suction balance assist bar is for balance assistance only and not for body weight leverage.