Genexice Rotate & Lock Suction Cup Hook Do NOT buy from other vendors if you want the original high quality product! Look for "Sold by Genexice, Inc." and buy the original brand. Easy installation without glue or tools via rotate and lock suction technology Suction ONLY works on ceramic tile, mirror, glass and acrylic surfaces Suction does NOT work on granite, marble, porcelain, quarry, stone, wood, dry painted wall, metal, brick or any surfaces that are rough, uneven or porous Suction Cup Dimensions: 2.5" diameter, Hook Length: 1.75"