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 0.30" thick rubber butt-pad which provides positive shoulder purchase to prevent slippage even with body armor or modular gear. Made in U.S.A. FEATURES Mounts on mil-spec sized carbine receiver extension tube (not included) from manufacturers such as Colt, Armalite, S&W, LMT, and others (please see the note below) Supplemental friction lock minimizes accuracy robbing wobble* Sloping cheek weld combines a slim profile with user comfort Shielded release latch prevents snagging and accidental operation Premium chrome-silicon lock spring provides positive locking and long service life Side mounting slots accept optional cheek risers for NON AR15/M4 applications Removable 0.30" Rubber Butt-Pad offers an anti-slip surface and increases impact protection Compatible with Magpul ASAP®, ASAP® QD and other receiver-mount sling attachments Sling Mounts Rear - Push-button QD swivel sling mount accommodates up to 1.5" swivels (ambidextrous) Rear/Bottom - 1.25" sling loops Toe - Lanyard hole for custom para-cord rigs 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.