The SIG Sauer Folding Knuckle Stock Adapter (brand part number ADAPTER-X-FOLD) gives MCX and MPX pistol owners a way to install a proper stabilizing brace and fold the whole assembly out of the way when it’s not needed. It bolts on with a standard 1913 Picatinny interface, so it works with existing Picatinny-compatible braces rather than requiring a proprietary mount. Finished in black to match factory furniture, it’s a straightforward, purpose-built add-on for shooters who want a folding footprint on their MCX or MPX build.

Key Specifications

• Built for the SIG Sauer MCX/MPX pistol platform.
• Uses a standard 1913 Picatinny interface for brace attachment.
• Allows the brace assembly to fold for a more compact footprint.
• Finished in black to match factory furniture.

Frequently Asked Questions

What does this adapter do? It lets you install a proper stabilizing brace on your MPX or MCX pistol and fold the brace assembly.

What interface does it use? A standard 1913 Picatinny interface.

What platform is it built for? SIG Sauer MCX and MPX pistols.

Buy the SIG Sauer Folding Knuckle Stock Adapter, MCX/MPX, 1913 Picatinny, Black

Add a folding footprint to your MCX or MPX brace setup. Order it from our SIG Sauer lineup, part of our stocks and braces selection, at our Lubbock, Texas gun shop for fast, direct shipping.