Jardin Plastic Tank Aquarium Check Valves for Air Pump, 5-Piece Product name: check valve Use for: fish tank, aquarium; hole diameter: 2 7mm/0 1" Overall Size: 3. 5 x 1. 7cm/ 1. 4" x 0. 66"(L*Max. D) Material: Plastic; Color: White; Weight: 9g Package content: 5 pcs x aquarium check valve