uxcell 20-Piece Plastic Aquarium Water Stop Check Valves Set Aquarium Check Valve; Fit for : Aquarium Dimension : 1.5 x 5.3cm/0.6" x 2.1"(Mad*L);Ports Outer Dia : 5mm/0.196" External Material : Plastic; Color : Clear, Pink Weight : 75g 20 x Aquarium Check Valve