The B.R.E. The Samson Bufferless Receiver Extension with picatinny folding stock adapter is a 6-position adjustable carbine buffer tube designed to seamlessly integrate with mil-spec AR-15 carbine stocks. Folding Mechanism can be removed and reattached for right side fold. Attach to the Brownell’s BRN-180, Sig Sauer MCX, Sig Sauer MPX and other buffer less set ups. Stock not included.