Magpul MAG310-ODG CTR Carbine Stock OD Green Synthetic for AR-15, M16, M4 with Mil-Spec Tube (Tube Not Included)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 Mil Spec Model includes a standard 0. 30" thick rubber butt pad which provides positive shoulder purchase to prevent slippage even with body armor