Simple and indispensable check valve attaches in the airline between the air pump and top of aquarium and prevents water from back siphoning into your air pump and causing water damage. Easy to install.
InstructionsLook for the words air in and air out on check valve. Install valve in the airline between pump and the top of aquarium (outside aquarium). Lee's Check Valve is intended for use on all aquariums where the air pump is on a level lower than the water surface.Install only as directed.