FailZero Bolt Carrier Group Bolt Carrier Group Silver No Hammer Nickel Boron. 8 SPC Bolt Carrier Group (BCG) comes fully assembled and ready to drop into most Mil-Spec upper receivers chambered in 6.8 SPC. All critical parts are coated with EXO Nickel Boron technology that provides permanent dry lubricity" extreme durability and increases both wear and corrosion resistance. Specifications for FailZero Bolt Carrier Group Bolt Carrier Group: Manufacturer: FailZero Color: Silver Finish: Nickel Boron Hand: Right Additional Features: No Hammer Bolt Carrier Group Last Chance: Yes Case Finish: Nickel Boron Handle Color: Silver Features of FailZero Bolt Carrier Group: Nickel Boron treated Package Contents: FailZero Bolt Carrier Group