Adaptable Carbine/Storage (ACS) stock is a drop-in replacement for standard USGI M4 collapsible stock that gives the tactical operator extra storage options, a secure, comfortable cheekweld, and an advanced dual-locking lever. Smooth, streamlined exterior contours prevent snagging on clothing, sling, or vegetation, and help ensure fast exits from vehicles without snagging on gear. Removable battery storage compartments run the full length of the extra-wide comb and hold 2 AA or 3 CR-123 batteries, while providing a wide, contoured area for an exceptionally solid, comfortable cheekweld. Secure molded rubber caps keep water and dust out of compartments and face the rear of the stock for eas Mfg: Magpul SPECS: Reinforced molded polymer, Black, Dark Earth or O.D. Green. 77/8" (20cm) OAL, 5 1/4" (13.3cm) high. 13.6 oz. (385g) weight. Mil-Spec fits mil-spec 1.14" O.D. carbine buffer tubes..