Quantity:1 batteries required:No Batteries Included:No Item Weight:23 g Specification: Conditon: 100% Brand New Item Type: Check Valve Material: Plastic Color: As Pictures ShownQuantity: 10pcs Package List: 10 x Check Valve About this item Prevent the water in the fish tank from flowing back into the air pump and burn the air pump to avoid danger. Protect you air pump by preventing aquarium water from back siphoning during a power outage. The check valves are for common aquarium air pumps. Please DO NOT use them with CO2 system. Great one way check valve for aquarium and fish tank. We greatly value our customers and want you to be completely satisfied with your purchase. If you aren't happy with your shopping experience or product, we urge you to contact us so we can resolve the issue! When the position of the air pump is lower than the water surface, prevent the backflow of water from damaging the front air pump or other equipment. After adding the check valve, the air pump can be placed above the water surface or below the water surface, and there will be no backflow of water when the air pump stops working. Using plastic material, beautiful and durable. Unique plunger design, provides reliable, tight shut off, compact and convenient.great gifts for old people See more product details Prevent the water in the fish tank from flowing back into the air pump and burn the air pump to avoid danger. Protect you air pump by preventing aquarium water from back siphoning during a power outage. The check valves are for common aquarium air pumps. Please DO NOT use them with CO2 system. Great one way check valve for aquarium and fish tank. We greatly value our customers and want you to be completely satisfied with your purchase. If you aren't happy with your shopping experience or product, we urge you to contact us so we can resolve the issue! When the position of the air pump is lower than the water surface, prevent the backflow of water from damaging the front air pump or other equipment. After adding the check valve, the air pump can be placed above the water surface or below the water surface, and there will be no backflow of water when the air pump stops working. Using plastic material, beautiful and durable. Unique plunger design, provides reliable, tight shut off, compact and convenient.great gifts for old people