uxcell Aquarium Air Pump Co2 Diffuser Red Plastic One Way Check Valves 11 Pcs Product Name : Aquarium Check Valve;Use for : Fish Tank, Aquarium Hole Diameter : 2mm/ 0.08";Total Size : 5.3 x 1.5cm/2.1" x 0.6"(L*Max.D) Material : Plastic;Color : Clear, Red Weight : 41g Package Content : 11 Pcs x Aquarium Check Valve