The magpul str (storage/type restricted) is a drop-in replacement buttstock for ar15/m4 carbines using mil-spec sized receiver extension tubes.A storage-capable version of the ctr the str has improved cheek weld and two water resistant battery tubes on a compact reinforced polymer a-frame design.The str incorporates two integral sling loops a reversible push-button qd sling mount and a replaceable 0.30" thick rubber butt-pad which provides positive shoulder purchase to prevent slippage even with body armor or modular gear.Firearm Type: AR-15Firearm Model: AR-15Material: PolymerFinish: OD GreenFeatures: Water-Resistant Battery Storage TubesAdjustment Type: CollapsiblePositions: 6Length Of Pull: 10.90"-14.20"Tube Included: No