It functions just like suction cup hooks that stick on mirrors, windows, kitchen Cabinets, tile, whiteboards, metal and many other smooth surfaces; This phone case has a sticky layer that consists of million nano sized suction cups, so when you stick it to a flat surface, make sure you wipe the surface clean and dust free; Stick the case on the surface and push out any air that may be trapped inside; It never leaves a mark on anything you stick