ITEM NAME:1X Fine Aquarium Non-Return Air Pump Check Valves ME 1X non-return check valves foraquarium air pump. They are made of plastic material for long time use. The aquarium valves are important accessories for air pumps. Measuring approx. 2.08" long, 0.56" diameter. tip outside diameter: ~0.18" 1 x check valves Specially designed Non-Return Valves will protect you air pump by preventing aquarium water from back siphoning during a power outage.Place these Air Pump Valves in your airline tubing between your air pump and aquarium water to prevent water returning down the air line.Total Weight: 9g. Box Contains 1x Check Valves Preview.1x Check Valves.