USED SIG SAUER Stock Adapter - 1913 Interface Folding Knuckle SIG MCX / SIG MPX Black ADAPTER-X-FOLD. Install these AR15 Stocks from SIG SAUER using the integral 1913 rail on the receiver. Using the genuine Stock Adapter - 1913 Interface Folding Knuckle while creating a better shooting experience. Convert your Sig now with the easy to install SIG SAUER Stock Adapter - 1913 Interface Folding Knuckle. Specifications for SIG SAUER Stock Adapter - 1913 Interface Folding Knuckle: Manufacturer: SIG SAUER Gun Make: SIG Sauer Color: Black Gun Model: SIG Sauer MCX SIG Sauer MPX Hand: Ambidextrous Condition: New Fabric/Material: Metal Features of SIG SAUER Folding Stock Adapter for MPX/MCX 1913 Interface ADAPTER-X-FOLD: Designed for use with SIG SAUER MCX/MPX firearms and compatible SIG SAUER stocks. Allows folding for storage and transport. Attaches to 1913 rail on rear of MCX/MPX. Compatible with standard size buffer tubes. Package Contents: SIG SAUER Stock Adapter - 1913 Interface Folding Knuckle SIG SAUER Infinite Guarantee What firearm models does the manufacturer say SIG SAUER Stock Adapter - 1913 Interface Folding Knuckle is compatible with? The manufacturer suggests that SIG SAUER Stock Adapter - 1913 Interface Folding Knuckle is compatible with SIG Sauer MPX SIG Sauer MCXSIG SAUER ADAPTER-X-FOLD: Stock Adapter - 1913 Interface Folding Knuckle SIG MCX / SIG MPX Black