About this item [Smooth surface application]: Our suction cups can be vacuumed on all smooth surfaces such as windows and glass, ceramic tiles. But the water may cause it to fall off. [Easy to Organize]: The included wire and transparent knurled nut make it easy to organize the space of the kitchen accessory and make installation of DIY furniture or hold decorations etc. [Dimensions]: diameter: 40mm, height of M5 thread: 10mm. [Quantity]: 8 pieces.