Bravo Company's BCM Mil-Spec Carbine Stock Hardware Mounting Kit (Mil-Spec) for M4 contains all the necessary parts to mount your Mil-Spec dimension stock assembly to your lower receiver, receiver extension (Mil-Spec 6-position) receiver end plate, lock nut (Castle) M4 and action spring carbine buffer assembly. Carbine Std (options for H, H2). This kit is compatible with the plastic stocks from - BCM, VLTOR, LMT, Magpul CTR-M, Stag Arms and Colt. Features: This kit is compatible with the plastic stocks from BCM, VLTOR, LMT, Magpul CTR-M, Stag Arms, Colt