I have also tried to identify your item, without success. None of the larger worldwide brands seems to have anything exactly like it.
I suspect 'sintered plastic adjustable pneumatic silencer' or 'sintered plastic manually adjustable throttling pneumatic silencer' would be a better description. If you are looking for a replacement I would suggest you search for above, but without the 'sintereed plastic' description and select and test one in sintered metal instead.
It would cost to much if you need thousands, but might under circumstances give a better performance and lifetime.
Note: The above is based on the impression that the top screw is also for adjusting the outlet, not for fastening, demounting and cleaning of inner parts only.