This attachment solution is an adhesive system developed by nie wieder bohren Germany. The system was designed for use on tile, stone, glass, metal,mood and most plastics. The caddy installs simply with no measuring, no tools and has a Lifetime Warranty on the mounting system. The caddys are made of solid brass material and finished in Chrome, Oil rub bronze, Atlas Copper Bronze and Black Bronze and are 100% rustproof. As a bonus the system can be removed if needed with no damage to the surface. You can watch the installation video on Houzz to see how it works.