Features: 1.Prevent water backflow from damaging front-end air pumps or other product equipment 2.Non return air pump safety valve, an essential accessories of pump 3.Greatly protect the oxygenation pump from damaging by water retrograde into pump 4.Prevent the risk of water returning when the pump is shut down and stopped working 5.Suitable for aquarium, fish tank, fishing tackle shop, etc Specification: This check value can be used to prevent water backflow from damaging front-end air pumps or other product equipment. Perfect for aquarium, fishing tackle shop, etc. Features: 1. Prevent water backflow from damaging front-end air pumps or other product equipment. 2. Non return air pump safety valve, an essential accessories of pump. 3. Greatly protect the oxygenation pump from damaging by water retrograde into pump. 4. Prevent the risk of water returning when the pump is shut down and stopped working. 5. Suitable for aquarium, fish tank, fishing tackle shop, etc. Specification: Item Type: Aquarium Check Valve Material: Plastic Optional Color: White, Red, Black Quantity: 10Pcs Item Size: 10 * 10 * 3cm / 3.9 * 3.9 * 1.2inch Package Weight: Approx. 30g Package List: 10 * Aquarium Check Valve Note: One check valve is required for each outlet. Two-head air pump requires two check valves.