4pcs Aquarium Check Valves for Common Air Pumps,Aquarium Air Pump Check Valves Red Clear Plastic One Way Non-Return Check Valve AquariumAir Pump Accessories for Airline Tubing Fish Tank(4mm)

Let's plenty of air through, Don't do what I did & not fit them to your air line because you will end up buying new aquarium pumps & new carpets & ceiling re-plastering. Plenty cheap enough to buy

Excellent valves to stop the water from my air pump flowing back up the pipe & very cheap so I have 2 spare. Great communication & speedy service.

Cheap and works fine.

Perfect use as the non return valve for a Dudley toilet flush button. It restricts the volume of water that can leak back into the air flush tube Therefore it gives easier flush.

Came quickly. Doesn't he job.

Dose the job

Easy to fit and far cheaper than my local pet store

Fit 6mm piping perfectly, but not all of these valves worked despite me blowing like mad. The ones that did are working perfectly and the airflow is great, bubbles are super - though that also depends on your pump. Would think twice about buying these again.