TacFire .750in Adjustable Steel Gas Block Gen 3 Black Small. This model allows you to tune your AR-15 rifle or pistol to shoot specific loads or run with specific gas lengths to shoot lighter and cycle more reliably. This model also features a low-profile and is designed to be used with free-float handguards. Specifications for TacFire .750 Adjustable Steel Gas Block: Manufacturer: TacFire Color: Black Fabric/Material: Steel Gas Block Journal Size-Diameter: .750 in Features of Tacfire .750 Adjustable Steel Gas Block Gen. 3: Modularity and control over AR-15's gas system Tune AR-15 rifle or pistol to shoot specific loads Run with specific gas lengths to shoot lighter Cycle more reliably Low-profile design Package Contents: TacFire .750 Adjustable Steel Gas Block TacFire MAR001S-ADJ-G3: .750in Adjustable Steel Gas Block Gen 3 Black Small