These hooks can stick to smooth and hard surfaces such as tile, metal, glass, wood, etc., but are not suitable for painted walls, drywall, wallpaper and rough surfaces, once stuck to these surfaces, they cannot be removed and may damage the wall. Please do not hang valuables. INSTALLATION STEPS: Before installation, clean and dry the surface of the wall, peel off the backing film and stick the hook on the freshly cleaned wall. Place the hook firmly on the wall and let it sit for 24 hours to maximize adhesion. Once you have completed these steps, you are ready to hang your desired items on the hook!