Cry Havoc Tactical 223 One Pin QRB Barrel Locking Plate Kit - Pistol Gas Tube. The QRB Kit can only be used on Barrels with a maximum outside diameter of 0.985in and Free Float Hand Guards with a maximum width of 2.0" Also the QRB will add 1.5in to the length of your free floating hand guard. For Caliber or Barrel Length Change - Includes Barrel Plate and Gas Tube. The 2-Pin option is the Military Model Currently in use by the United States Air Force. NOTE: If you have a GEN-1 QRB The 2-Pin version will not work. Specifications for Cry Havoc Tactical 223 One Pin QRB Barrel Locking Plate Kits: Manufacturer: Cry Havoc Tactical Gun Make: AR Platform Gun Model: AR-15 Color: Black Condition: New Last Chance: Yes Projectile Caliber: .223 Caliber Package Contents: Cry Havoc Tactical 223 One Pin QRB Barrel Locking Plate Kits Barrel Plate Gas Tube Cry Havoc Tactical 793888121812: 223 One Pin QRB Barrel Locking Plate Kit - Pistol Gas Tube