The SB Tactical MPX-01-SB Adjustable Pistol Brace SIG MPX & MCX is a three-position adjustable pistol stabilizing brace engineered for receiver cuts on SIG SAUER SIG MPX and SIG MCX platforms.It ships as a complete, ready-to-install assembly with an integral M1913 adjustable housing. MCX compatibility requires a genuine SIG MCX lower receiver; the SIG MCX Stock Adapter Kit is not compatible. Excludes SIG MPX Copperhead.Three-position adjustment for configurable length.Compatible with SIG MPX and SIG MCX platforms, except MPX Copperhead.Complete assembly includes integral M1913 adjustable housing.Select the MPX-01-SB for platform-specific fit and a precise, installation-ready brace assembly for compatible receiver configurations.