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)

Very reasonably priced. All function as they should.

Bought for my ponds air pump. Cheap enough and do the job. HOWEVER…….I did get a dud valve in the first pack I bought (wouldn’t let air through. I think that when it was glued together, excess glue sealed the valve shut), and the plastic it’s very brittle and it doesn’t take much for it to crack/split, especially when the ambient air temperature changes.

Good product

Very good useful valves, great price, easy to fit.

Good product works as should do

Good value

Came quickly. Doesn't he job.

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.