Product DescriptionThe FailZero M16/M4 Bolt Carrier Group (BCG) comes fully assembled and ready to drop into most mil-spec M16, M4, or AR-15 upper receivers. All critical components are treated with FailZero&&';;s EXO Nickel Boron technology to deliver permanent dry lubricity for smoother cycling, extreme durability, and enhanced wear and corrosion resistance in demanding conditions.Product Highlights Fully assembled bolt carrier group designed for quick drop-in installation EXO Nickel Boron treatment delivers permanent dry lubricity to reduce friction Enhanced wear resistance for extended service life in high-round-count use Improved corrosion resistance for reliability in harsh environments No-hammer configuration (as specified by manufacturer) Specs Brand: FailZero Product Type: Bolt Carrier Group (BCG) Platform Fit: Mil-spec M16 / M4 / AR-15 upper receivers Coating/Finish: EXO Nickel Boron, Black finish Material: 8620 steel MPN: FZ-M16/4-01-NH-BLACK UPC: 094922014276 Disclaimer: We strive to provide accurate and up-to-date product descriptions, specifications, and images; however, errors or omissions may occasionally occur. We are not responsible for any inaccuracies or discrepancies in the content provided. If you notice anything incorrect or unclear, please contact us so we can correct it. When in doubt, we recommend verifying details directly with the product&&';;s manufacturer.