Magnet Source 07254 Magnetic Hook, 35 lb Weight Capacity, 2-Hook, Chrome

They hold through glass! simply place a magnet on each side of the glass, then hang the sign or decoration. Can be used with single pane windows or as single hooks on metal doors. If used on a metal surface, each hook will hold up to 35 lb protective coating helps prevent scratching. Recommended use for single-pane windows only.