A check valve is an essential accessory when installing an air pump for your aquarium. Due to gravity, water will always try to find its own level, which means that if your air pump is placed below the water level, you risk flooding in the event of a power failure.
The addition of an inexpensive one-way check valve can save you the trouble of flooding your aquarium. They are designed to allow flow in one direction only, so they will allow the pump to push air into the aquarium, but will not allow water to flow back from the aquarium to the pump.

SPECIFICATIONS:

Product: Non-Return Check Valve
Colour: Red
Quantity: 5/10PCS Non-Return Check Valve

Notes:

1. Please allow slight chromatic aberration in the photo
2. Due to manual measurement, the size may deviate