The Magpul ACS-L (Adaptable Carbine Stock - Light) is a drop-in replacement buttstock for AR15/M4 carbines using mil-spec sized receiver extension tubes. A streamlined version of the ACS, the ACS-L utilizes the same center storage compartment and cheek weld but removes the battery tubes for a slimmer, lighter weight package.Made in U.S.A.FEATURESMounts on mil-spec sized carbine receiver extension tube (not included)Sloping cheek weld provides a wide contact surface for user comfortStorage compartment in tail of stock with positive latching access door on right hand sideSupplemental friction lock minimizes accuracy robbing wobble*Shielded release latch prevents snagging and accidental operationPremium chrome-silicon lock spring provides positive locking and long service lifeReplaceable 0.30" Rubber Butt-Pad offers an anti-slip surface and increases impact protectionCompatible with Magpul ASAPA(R), ASAPA(R) QD, and other receiver-mount sling attachmentsSling MountsMid - Included reversible Sling Mount Kit - TYPE 3 fits up to 1.5" push-button swivels (swivel not included)Rear/Bottom - 1.00" sling loop NOTE: There are two basic sizes of M4 Carbine receiver extensions (buffer tubes): mil-spec and commercial-spec. If you have a commercial-spec extension on your rifle, make sure to order the Commerical Spec ACS-L.