Corrosion Resistant: Suction shower shelf is made up of all high-quality materials to prevent any rusting/corrosion and to impart it a longer life. Warm Tip - If problems when firstly installation, please wash the suction cup, dry it with hair dryer and test it on the smooth glass surface. If suction holds, that means initial wall might not applicale for using suction cup, please change installation location or use 3M Discs first which we have provided in the package. ATTENTION - Suction will not work over grout lines or on porous surfaces such as: WOOD, unfinished MARBLE, GRANITE, porcelain, wallpaper, natural stones (such as Travertines), painted wall & any surface that is bumpy, etc... 3M Adhesive Mounting Discs Included: To install your suction shower basket on a concave and convex rough surface, you'll need to use the 3M Discs first which we have provided in the package. If you have any questions or concerns with your order, you can conveniently contact us. We have an awesome Customer Service Team and will do whatever it takes to make it right for you!