MUST MOISTEN CUPS FOR OPTIMAL SUCTION. Suction Assist Bars help you keep your balance while in the shower, bath, kitchen or anywhere you need a little support. Suction cups attach to any smooth surface. The red or green indicators let you know when they are securely in place. This is not a weight bearing grab bar. It is for balance assistance only. Your surface MUST be SMOOTH with no texturing or grain on wall. Your wall should be clean and free from soap residue or water deposits. NO TILE