When you turn off the air pump to stop the oxygen delivery, if you do not install a check valve on the air pipe, the water in the fish tank will produce a siphon reaction and damage the air pump.
Place these air pump check valves in your airline tubing between your air pump and aquarium water to prevent water returning down the air line.
Fits standard aquarium airline tubing with inner diameter about 4mm.
Air pump accessories for fish tank oxygen system. To prevent water from flowing back into the air pump. NOT suitable for high-pressure systems to avoid crack and leak.
Installed in the correct way, no noise will be generated during operation.