The Compact AR/MCX Stock Adapter allows the user to mount a picatinny-style stock attachment (such as the SIG MPX folding stock or SB Tactical FS1913 brace) in place of an AR15 style buffer tube
The kit is composed of two parts and an attaching bolt.
The externally-threaded adapter plug fits into the threaded buffer socket or ring.
The adapter rail section firs into the slot in the adapter plug and the two are secured to each other and the firearm by a hex-socket bolt and lock washer