The Magpul ACS Stock is a drop-in replacement collapsible buttstock for AR15 rifles usings mil-spec sized receiver extension tubes. The ACS has improved cheek weld and features an integrated rear storage compartment for spare parts and other gear, water tight battery storage tubes on both sides, and ambidextrous QD sling swivel studs. Also features a shielded operation lever and the unique Magpul cam-lock design to minimize stock movement on buffer tube for a tight fit. Has a replaceable 0.30" rubber butt-pad which provides a positive shoulder purchase to prevent slippage even with body armor or other field gear.