Place in your airline tubing between your air pump and aquarium water to prevent water returning down the airline How to clean Unscrew and open up check valve pinch the rubber boot inside valve to make sure small slit is open Otherwise no air to tankBe attention: Please DO NOT use them with cO2 system Made of durable clear plastic Package Weight: 25 g1oz

For Oxygen Pumps Only: great 1-way check valves for most common aquarium air pumps DO NOT use them in cO2 or other high-pressure systems to avoid cracking or leakage Small & Light: Size: 166 L x 05 W Diameter of air holes: 012 Weight: 007 oz Standard ID airline tubing: 316 Add little weight to your hose for smooth airflow Ideal Pump Protectors: Effectively prevent water backflow during a power outage or pause of the pump Ideally protect your pump and reduce your loss when youAre at work or on vacation Sturdy Plastic: Dependable plastic which can be tightly connected to the hose without air leaks or restrictions Always keep your fish lively and endure long-time use Detachable Design: Easy to detach it for cleaning and maintenance without using tools Please stick something into the hole to poke it open when it gets clogged and restricts air flow