The SIG MCX in a discrete platform ? featuring a folding pivoting contour brace and a 5.5" barrel with PDW upper.Rapid deployment, thin, agile and precise. This is the SIG MCX® Rattler. Featuring a 5.5" PDW barrel, the MCX platform has never been more compact or accessible. Ready to go wherever it's needed, the MCX Rattler PCB features a folding pivoting contour for stability and easy concealment. This gun was designed from the ground up to be as discrete as possible while retaining all the robust capabilities of the MCX. Free-floating M-LOK® handguards matched with a PDW upper and 5.5" barrel, the MCX Rattler PCB is the ideal choice for fast-moving operators. M-LOK is a registered trademark of Magpul Industries Corp.