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 (not included). Attach to the Sig Sauer MCX, Sig Sauer MPX and other buffer less set ups.FeaturesCompatible with mil-spec AR-15 adjustable carbine stocks6 position adjustableFolding Mechanism can be removed and reattached for right side foldRamp to drastically improve ease of installing AR-15 stockSkeletonized to reduce weight