The KNS Precision Compact AR-MCX Adapter with Flange provides the advantages and versatility of AR/MCX adapters without the added rail length that locks into the rear AR15 receiver stock plate pocket, allowing you 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. This modular solution is ideal for firearms that utilize the buffer tube attachment to mount stocks or braces but do not require the tube for an inline buffer spring, offering a clean, compact way to attach stocks or other accessories while preserving overall weapon balance. The kit consists of two parts and an attaching bolt; the externally-threaded adapter plug fits into the threaded buffer socket or ring, while the adapter rail section lockingly engages the plug and is secured to the firearm with a hex-socket bolt and lock washer, delivering a secure, low-profile attachment. Designed for AR rifles where the carrier and buffer tube do not protrude past the receiver ring, this stock adapter expands customization options without altering the receiver geometry, making it a practical choice for versatile, compact builds.