The SCW Stock Upgrade Kit is specifically made for previous Dead Foot Arms customers who already own the MCS AR-Pistol Kit (2.5 or 4") or MCS Folding Stock Adaptor and want to transition their current product to the SCW 2.5 or SCW 4 Stock. The SCW Stock Upgrade Kit retrofits directly to the MCS AR Pistol kit (MCS Short Buffer Tube). Simple installation, 5 adjustable length settings, comfortable design, and designed and manufactured in the USA.