Rosco Manufacturing V2 Non-Adjustable .750 Gas Block Black. Our Non-Adjustable gas block is a direct plug in for any one of our barrels and has provisions for pinning. Each Gas Block comes with (2) set screws and (2) roll pins. Specifications for Rosco Manufacturing V2 Non-Adjustable .750 Gas Block: Manufacturer: Rosco Manufacturing Color: Black Gas Block Journal Size-Diameter: .750 in Country of Origin: USA Package Contents: Rosco Manufacturing V2 Non-Adjustable .750 Gas Block Rosco Manufacturing ROS-NGB-002: V2 Non-Adjustable .750 Gas Block Black