* The place where the suction cup can be attached is a glossy flat surface, mainly tiles, stainless steel, mirrors, transparent glass, metal-painted surfaces, etc. that are larger than the suction cup. * Do not install on uneven, rough, matte surfaces, or scratched areas where air enters between the mounting surface and the suction cup and the suction force cannot be maintained. * Wipe off any dirt, moisture, oil, etc. on the mounting surface and suction cups before adsorbing.