The pad is made from heavy duty 3M adhesive. It attaches to fiberglass, metal, wood, rigid plastics and glass. Replacement pads are non-hardening and do not leave residue on the surface. The adhesive bonds on contact with the surface and will reach its full strength after 72 hours. Pads are designed to hold or support weight on flat, horizontal surfaces only and not vertical surfaces. Should not be used on copper, brass, or rough and porous surfaces such as unfinished wood or concrete.