underwater treasure Air Check Valve

underwater treasure Air Check Valve Product description Protect your air pump against water damage with the Underwater Treasures Check Valve. Connect the check valve in-line to the air tubing between your air pump and your aquarium. Ensure that the check valve is facing the correct direction (follow the diagram on the packaging). Connected correctly, the check valve will prevent water back-siphoning in the event of a power outage or air pump failure.