FailZero AR-15 5.56x45 NATO Bolt Carrier Group Stainless. All critical parts are coated with EXO Nickel Boron technology that provides permanent dry lubricity extreme durability and increases both wear and corrosion resistance. Patented Nickel Boron coating will reduce friction and improve the overall performance of your rifle. Specifications for FailZero AR-15 5.56x45mm NATO Bolt Carrier Group: Manufacturer: FailZero Color: Stainless Fabric/Material: Steel Caliber: 5.56x45mm NATO Gun Make: AR Platform Gun Model: AR-15 Weight: 9.6 oz Package Contents: FailZero AR-15 5.56x45mm NATO Bolt Carrier Group What firearm models does the manufacturer say FailZero AR-15 5.56x45mm NATO Bolt Carrier Group is compatible with? The manufacturer suggests that FailZero AR-15 5.56x45mm NATO Bolt Carrier Group is compatible with AR-15FailZero FZ-FULL-AUTO-LW-NH: AR-15 5.56x45 NATO Bolt Carrier Group Stainless