[Smooth surface application]: Our suction cups can be sucked on all smooth surfaces such as windows and glass, ceramic tiles. But 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 do DIY furniture installation or hold the decorations etc. [Dimensions]: Diameter: 40mm, M5 thread height: 10mm. [Quantity]: 8 pieces. [Good after-sales service]: If you have any problem with our suction cups, please feel free to contact us.