Haobase 6 Pcs Fish Tank Aquarium Red Clear Plastic Air Pump Check Valves Air Hole Diameter : 4mm/ 0.15";Overall Size : 5.3 x 1.5cm/ 2.1" x 0.58"(L*Max.D) Material : Plastic;Color : Clear, Red Package Content : 6 Pcs x Aquarium Check Valve