NRV (Non Return Valves)

Aquarium NRV (non return valve)is a one way valve that will prevent the back flow of water from an air stone to the air pump.

4 mm airline non-return check valve. Prevents aquarium water from siphoning out in case of a power failure.

Non-Return Valves will protect you air pump by preventing aquarium water from back siphoning during a power outage. 

Non-return valves (also known as check valves) are crucial components in any aquarium air or CO2 setup. These valves allow air or gas to flow in one direction only, preventing water from back-siphoning into your air pump or CO2 system, which can cause damage or electrical hazards. Non-return valves are easy to install and compatible with standard airline tubing. Ideal for use with air pumps, sponge filters, bubble walls, and CO2 systems.