The thing the buffer goes in to on an AR.
I'm looking for a multi-position tube - mil-spec.
I have a standard A2 tube on the AR right now, and I want to put a collapsible stock on it.
Let me know what you have - I'd like to spend no more than 30 bucks or so, but that'll depend on what you've got and what comes with it (just the tube vs tube, buffer and spring, etc).
Thanks!