Jardin Plastic Aquarium Tank Air Pump Blue Check Valves, 6-Piece Product name : aquarium check valve; use for : fish tank , aquarium Hole diameter: 2mm;total size: 3 4 x 2cm/1 3 x 0 8"(l*d) Material: Plastic;Color: Blue Weight : 12g Package content : 6 pcs x aquarium check valve