Product description Pack of 10 red one-way valves Pump check valvesair are manufactured atMade from durable plastic materials and designed to adapt to any environment.most water pumpscommon aquarium air without making noise.Prevent your pump from overheating.air to flow water through your pump during water changes or when power is interrupted.Note: Please do not place the air valves in the CO2 system as the high pressure will cause them to crack and leak. Mount standard 4mm hoses Good air flow and no restrictions Made of plasticHard rigid Durable and aging resistant Long working time without noise How to install 1. Before use, clean and dry both sides of the tube in order to hook the valve well.2. Check the flow direction of the valve to make sure it is placed on the correct side.3. Carefully attach the pump check valve to the pump.air to the tube and connect it completely.Tips: If the valve restricts the air flow in both directions, please insert something into the hole on the valve side.input to push the valve.After that, the valve would allowthe air to flow in the right direction. Read more Good in prevention The air check valve protects the pump from damage.air by preventing aquarium water from siphoning during a power outage. Practical application Fits standard 4mm hoses.Can be usedfor aquariums, fish tanks and hydroponic gardening etc.But DO NOT place them in a CO2 system. Safe and durable Clear rigid plastic materials allow you to get rid of inlet breakage easily or water leaksair.Work for a long time without making noise. Type Check Valve Air Valve Connector Quantity 10pcs Color Red Connector diameter 4mm