FeaturesWhen the oxygen pump stops working, the water in the aquarium may return to the inlet pump, causing damage to the air pump. A check valve can solve this problem. The check valve can prevent the air pump from entering the water and is an essential accessory. Our check valve is made of materials, wear-resistant and durable, not easy to corrode and age. The noise of the check valve is very low when used, and it will not affect your normal rest, even at night. Qne-way valveOur check valves are one-way valves that can effectively prevent water backflow. After the installation is completed, the check valve will slightly reduce the air outlet, but this does not 'will not affect the normal use of the air pump. Small SizeOur check valves are black and compact.