Great. It's a three lug coupler system and so I was told I had to make sure the lugs "seated" properly by tightening the suppresser every 5 rounds or so for the first 50 to 100 rounds. Carl O'Quinn at STW (very knowledgable guy and very accessable) sorta walked me through the whole breaking in process. He indicated that the lugs might be a little loose at first before they seated properly. I had no problems at all and the suppressor stays on tight during firing. This suppressor, from all accounts, is one of the most reliable out there. Will not "shoot off" like some others.
It's made of titanium and is very light. The finish matches, exactly, my Colt M4 upper. Oh yea, did I mention that it's quiet as hell. Without subsonic, it's more quiet than a .22 and with subsonic, it's silent. I have only fired 4 rounds of subsonic through it- it won't cycle with the stuff I'm using- I don't know if any True subsonic .223 will cycle, although I could be wrong.
I love it. Anyone want to talk to Carl, call him at 919-471-6778.