It is an air valve. It does what it is suppose to do. No complains.
They all leak past the adjustment screen. No real big deal. Just used a little plumber's tape and stopped the leak.
These work great. I bought these to replace one that stopped working (different brand) on my sponge filter line. Keeping extra of these on hand in case I want to add lines or replace old valves.
I have tried numerous valves and these are by far my favorite. You don't have to tighten them too much to completely cut off the air if need be and adjusting the flow is easy. Highly recommend.
These air valves are economical and work like a charm. Will be ordering some more before too long.