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/M16 applications • Removable 0.30" Rubber Butt-Pad offers an anti-slip surface and increases impact protection • Compatible with Magpul ASAP® 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 Optional Accessories** • Extended Rubber Butt-Pad, 0.55" • Enhanced Rubber Butt-Pad, 0.70" • Cheek Risers (0.25", 0.50", 0.75" for NON-AR15/M16 applications) Specifications** • CTR, Mil-Spec (stock configuration) • Weight: 0.55 lb. • Weight, w/ Rec. Extension: 0.80 lb. • Length, Maximum: 6.90 in. • LOP Adjustment Range: 3.25 in. • LOP, M4 Collapsed: 10.70 in. • LOP, M4 Extended: 13.95 in. 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. Please see the "Related Info" section above to determine which tube you have. If you happen to have one of the uncommon military tubes with an extended slant-back, along with the Mil-Spec CTR you will also need to order the Extended Rubber Butt-Pad, 0.55" (sold separately). * Friction lock performance may vary depending on the host receiver extension's dimensional tolerances. ** Specifications based on standard-length (flat-back) M4 Carbine receiver extension and may vary depending on tube manufacturer. Standard Rubber Butt-Pad, 0.30" weight: 0.08 lb. Optional Extended Rubber Butt-Pad, 0.55" weight: 0.11 lb. Optional Enhanced Rubber Butt-Pad weight: 0.13 lb.