Sig Sauer X-Fold Adapter Assembly

This is an OEM Sig Sauer X-Fold Adapter Assembly. This part allows you to install a buffer tube on a MPX or MCX using the factory 1913 rail section on the rear of the firearm. On a MPX/MCX pistol you can install a pistol buffer tube and pistol brace while on a rifle you can install an AR15 buffer tube and stock. This can be used on a 556, 556xi, or 552 in conjunction with the "PSB Buffer Tube Adaptive Kit", P/N: ADAPTER-PSB-1913-BLK.