10pcs Air Pump Check Valves Pipe Fitting for Aquarium Fish Tank CO2 Water Air Line Pump One Way Non-Return Actuator Check Valve

Works like it should thanks

No complaints... Good price and works as it should.

So after some experimentation, I figured out that the whistling is caused if the check valve vibrates too much. It would be fine on lower settings of my air pump, but one I cranked up the power the whistling was non-stop. All of my tanks are in my room, so that is a no go. All of them run on air pumps, and I've figured out with some trial and error how to keep everything practically silent.For this check valve, the solution was as simple as resting the air pump on a small towel and putting a rock on top of the check valve. Not the most elegant or aesthetically appealing solution but hey, it works.

Good quality. Quite a bit better than some others I have tried.

I've used these to stop back flow from my aquarium water back to my DIY CO2 generating system. Solved the issues immediately.

1 out of 4 check valves actually worked. Since only 1 was needed, it does the job, but going through the first 3 were very frustrating as they let water back in through the CO2 line.I'm using this for CO2 in an aquarium at about 35 PSI and 1 bps.

Works much better than the Walmart versions, I thought there was something wrong with my pump until I switched to this check valve, much better flow

All of them used , not brand new and only 4 is working poorly.

Half of them were completely blocked, the other half ranged from partially blocked to usable. I threw most of them out. This product has poor quality control.