Bravo Companys BCM Milspec 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,