Made with 8620 AISI steel and boasting a Manganese Phosphate finish, the Stern bolt fits into Mil-Spec and GlockA(R)-pattern upper receivers. It functions with Colt SMG, GlockA(R) magazines and it's fully compatible with standard AR15/M16 charging handles. Comes fully assembled with all sub-components installed, including firing pin/spring/retaining pin, extractor, and extractor spring. Also included in bolt assembly is a propriety center and roll pins. Compatible with Law tactical folding stock Compatible with Fostech Echo Trigger Mfg: Stern Defense