Pawfly 6 PCS Aquarium Air Pump Check Valves Red Clear Plastic One Way Non-return Check Valve for Fish Tank

Works as intended. Nice bright color makes them easy to locate behind the tank or inside tank cabinet. It whistles when you blow through it so it is very easy to determine the correct airflow direction.

perfect back flow valve, works great

Por lo menos para mi es un pesimo producto, prové varias valvulas de las que vienen en el paquete y ninguna logro retener el regreso del agua, ni colocandola por debajo ni arriba de la urna, termine quitandolas

It's been years since I've used check valves on my aquarium, mainly out of laziness. I recently had some water siphon into my air pump and decided to buy these. They are so much better than what was available years ago. These use a rubber diaphragm/reed valve rather than the old spring loaded disc. Much better design and no air flow restrictions whatsoever.

Excellent one-way check valve.. although not recommended, I've used these on an CO² tubing and they actually work better than some CO² C.V's I paid twice as much for.Would STRONGLY recommend for normal air pump lines on the aquarium.