Tatkraft Ferdinand Vacuum Screw Hard Rectangular Long Bath Shelf 45X18.9X5 cm Anti Rust 4-Layered Chromed Steel SIMPLE MOUNTING SYSTEM - For smooth polished, glass or tiles surface only! Easy installation - no screws, no nails, no glue, no tools! High durability, load capacity - up to 8 kg., tested by SGS International. Multiple usage - up to 1000 timeson smoothairtight surfaces PATENT PROTECTION: powerful vacuum downforce, membrane made of natural polymers Antirust 4-layer chrome plated steel:guarantees 2 times longer protection than a standard one (proved by 24-hour Salt Tests) ATTENTION - Will not adhere to unfinished marble, porous or rough surfaces(eg porous painted walls), or across grout lines