Complete Bolt carrier group, Machined from S7 Tool Steel, Lithium Isonite Coating, 4 Setting Adjustable Vent System relieves excess gas pressure created from suppressor use creating longer dwell time and less blowback to the shooter. Gas Adjustment can be turned while installed in the rifle, Uses all standard Mil- Spec components Staked Mil Spec Gas Key, Adjustment Pin is easily removed for cleaning Full Auto RatedWeight 11.40 oz