SIG SAUER MCX/MPX Folding Rifle Stock Black. It Installs Quickly And Easily To The 1913 Interface On The Firearm Receiver. Installation Allows Any Standard Ar-15 Type Butt Stock To Be Used. Specifications for SIG SAUER MCX/MPX Folding Rifle Stock: Manufacturer: SIG SAUER Gun Type: Rifle Gun Make: SIG Sauer Gun Model: SIG Sauer MCX SIG Sauer MPX Color: Black Condition: New Package Contents: SIG SAUER MCX/MPX Folding Rifle Stock SIG SAUER Infinite Guarantee What firearm models does the manufacturer say SIG SAUER MCX/MPX Folding Rifle Stock is compatible with? The manufacturer says that SIG SAUER MCX/MPX Folding Rifle Stock is compatible with SIG Sauer MPX SIG Sauer MCXSIG SAUER MCX/MPX Folding Rifle Stock Black STOCK-X-FOLD-CTR-BLK