Sons of Liberty Gun Works L89 AR-15 14.5 inch 223 Wylde Upper Receiver Group Medium Midlength 1-7 HUX Black. These uppers are built to the same standards as our legendary rifles and are test fired before leaving the shop. The L89 rails have 7-sided MLOK slots with integral QDs at the barrel nut on the left and right side. The L89 features the Drivelock barrel nut system anti-rotation tabs and an internal dowel pin between the upper/rail to all ensure a solid lockup with minimal POI shifts for attached laser or other VAS systems. Specifications for Sons of Liberty Gun Works L89 AR-15 14.5 inch 223 Wylde Upper Receiver Group: Manufacturer: Sons of Liberty Gun Works Caliber: .223 Wylde Barrel Length: 14.5 in Barrel Profile: Medium Gas System Length: Mid Length Barrel Twist Rate: 1-7 Muzzle Device: HUX Finish: Anodized Color: Black Fabric/Material: 416 Stainless Steel Handguard Length: 13.75 in Gun Make: AR Platform Gun Model: AR-15 Bolt Carrier Group Included: No Charging Handle Included: No Package Contents: Sons of Liberty Gun Works L89 AR-15 14.5 inch 223 Wylde Upper Receiver Group What firearm models does the manufacturer say Sons of Liberty Gun Works L89 AR-15 14.5 inch 223 Wylde Upper Receiver Group is compatible with? The manufacturer says that Sons of Liberty Gun Works L89 AR-15 14.5 inch 223 Wylde Upper Receiver Group is compatible with AR-15Sons of Liberty Gun Works U-M4L89-556-145-HUX: L89 AR-15 14.5 inch 223 Wylde Upper Receiver Group Medium Midlength 1-7 HUX Black