Product Description The 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 coating to deliver permanent dry lubricity, extreme durability, and improved resistance to wear and corrosion for smooth, reliable operation. This BCG includes a hammer and features a Nickel Boron finish for easy cleaning and reduced friction. Product Highlights Fully assembled, drop-in bolt carrier group for mil-spec AR platform uppers (M16/M4/AR-15) EXO Nickel Boron coating provides permanent dry lubricity for smoother cycling Enhanced durability with increased wear and corrosion resistance Nickel Boron finish helps reduce fouling buildup for easier maintenance Includes hammer (as specified by the manufacturer/distributors) Specs Brand: FailZero Manufacturer Part Number: FZ-M164-01-SAH UPC: 881314861842 Product Type: Bolt Carrier Group (BCG) Coating/Finish: EXO Nickel Boron / Nickel Boron Carrier Material: 8620 Steel Bolt Material: Steel Compatibility: AR Platform; fits M16, M4, AR-15 Condition: New 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.