Large one-way anti-return valve for aquarium and aquarium. Protect your air pump by preventing the water from the aquarium from sipping the back during a power failure. < / P> Made of durable transparent plastic. Net weight: 4g. Air hole diameter: 4 mm; Global size: 5.3 x 1.5 cm (l * max.d). Content of the package: 50 pieces x air-return valve. Pack of 50 red unidirectional valves The air pump valves are made from durable and designed plastics To adapt to most common aquarium air pumps without making any noise. Prevent your air pump from running water in your pump during water changes or when the power is interrupted. Note: Please do not place the air valves in the system. CO2 because the high pressure will cause them to crack and flee. Mount the standard 4 mm flexibles Good air flow and no restriction Hard plastic Rigid Durable and aging resistant Long operating time without noise How to install 1. Before use, clean and dry both sides of the tube to hang the valve. 2. Check the flow
