FOCUSPET Aquarium Suction Cup Fish Tank Sucker F 4/6mm Airline Tube Elastic holder clip, well clip easy to install/uninstall Suit for 4mm/6mm standard air line Diameter of Suction Cup: Approx. 2.7cm, Diameter of Clip: Approx. 6mm Can be used for aquarium airline tubing, check valve, CO2 tubing, diffusers Package Included:10x Aquarium Suction Cup