This is a NIB (New in Box), unfired SIG SAUER MCX Rattler factory-built pistol, chambered in .300 Blackout. Includes the original factory, matching-serial-number box, outer shipping box, factory .300 Blackout magazine, paperwork, owner’s manual, factory tools, sample SPEC-1 oil, cable lock, and SIG decal. SIG SKU: PMCX-300B-5B-TAP The factory-built Rattler features a 5.5-inch (140 mm) barrel, adjustable gas-piston system, ambidextrous semi-auto selector, SIG Enhanced Trigger, factory PCB locking side-folding brace, M-LOK rail system, Picatinny top rail, and a .300 Blackout three-prong flash hider.