JE Machine Tech AR-15 Low Profile Gas Block .750 Diameter .223/5.56/.300 BLK Black. 750 diameter(tolerance within .002) Roll pin included 2 hex head set screws Specifications for JE Machine Tech AR-15 Low Profile .750 Gas Block: Manufacturer: JE Machine Tech Color: Black Size: .750 diameter - tolerance within .002 Caliber: 5.56x45mm NATO .300 AAC Blackout .223 Remington Gun Model: AR-15 Additional Features: 2 hex head set screws and Roll pin included Features of JE Machine Tech AR-15 Low Profile .750 Gas Block: .750 diameter(tolerance within .002) Roll pin included 2 hex head set screws Package Contents: J&E Machine Tech AR-15 Low Profile .750 Gas Block What firearm models does the manufacturer say JE Machine Tech AR-15 Low Profile .750 Gas Block is compatible with? The manufacturer suggests that JE Machine Tech AR-15 Low Profile .750 Gas Block is compatible with AR-15JE Machine Tech TS-GB4: AR-15 Low Profile Gas Block .750 Diameter .223/5.56/.300 BLK Black