The Magpul CTR (Compact/Type Restricted) Mil-Spec model is a drop-in replacement buttstock for AR15 / M16 carbines using Mil-Spec sized receiver extension tubes. Designed for light, fast action, the streamlined A-frame profile avoids snagging and shields the release latch to prevent accidental activation. The CTR also features a supplemental friction lock system that minimizes excessive stock movement for enhanced weapon stability and an ambidextrous QD sling mount that will accept any push-button sling swivel. The Mil-Spec model includes a standard 0.3" thick rubber butt-pad, which provides positive shoulder purchase to prevent slippage even with body armor or modular gear. Made in the USA. Collection Collapsible Non-Storage AR Stocks Platform AR10, AR15, M4, M16, M110, SR25 Compatibility Mil-Spec sized carbine receiver extension tube (not included) from manufacturers such as Colt, Armalite, S&W, LMT, and others* LOP, M4 Collapsed ~10.5 in. LOP, M4 Extended ~13.8 in. LOP Adjustment Range 3.3 in. Length, max 6.9 in. Weight 9.0 oz. Weight, w/ receiver extension 13.0 oz Color FDE *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 Commercial-Spec CTR. Specifications based on standard-length (flat-back) M4 Carbine receiver extension and may vary depending on tube manufacturer. Friction lock performance may vary depending on the host receiver extension's dimensional tolerances.