uxcell 16 Pcs Black Plastic Aquarium Undergravel Filter + Air Line Hose + Tube Package Content : 16 x Fish Tank Undergravel Filter,1 x Tube,1 x Air Hose Line w Airstone;Material : Plastic Fit for : Aquarium Fish Tank Tube Size(Approx.) : 32 x 2.5cm/ 12.6" x 1"(H*D);Air Line Hose Size : 50.5 x 5mm/2" x 0.2"(L*D) Excellent material and easy to clean Different sizes could be made up to fit for different fish tanks