uxcell 3-Piece Plastic Aquarium Non-Return Air Pump Outlet Check Valves, Clear Check Valve Use for: Fish Tank, Aquarium; Hole Diameter: 1.7mm/0.06" Total Size: 5.3 x 1.4cm/2.08" x 0.55"(L* Maximum D) Material: Plastic; Color: Clear; Weight: 12g 3 Pcs x Aquarium Check Valve