DoubleStar Low Profile Gas Block .625in Black. .625"1045 steel and parkerized gas block designed to fit under most free floating handguard systems. Mounted with set screws. Specifications for DoubleStar Low Profile Gas Block: Manufacturer: DoubleStar Color: Black Fabric/Material: 1045 Steel Size: One Size Gun Make: AR Platform Gun Model: AR-15 Features of Doublestar Low Profile Gas Block Low Profile Gas Block Package Contents: DoubleStar Low Profile Gas Block What firearm models does the manufacturer say DoubleStar Low Profile Gas Block is compatible with? The manufacturer says that DoubleStar Low Profile Gas Block is compatible with AR-15DoubleStar DSC750L: Low Profile Gas Block .625in Black