Radian Weapons Model 1 AR-15 6mm ARC 14.5in Upper Receiver Mid Length 5/8x24 Nitride Black. Beyond quality and aesthetics the Model 1 features fully ambidextrous controls adding much-needed utility for both left and right handed shooters. Every Model 1 is assembled by hand one at a time by a trained gunsmith who inspects test fires and cleans the weapon to personally guarantee it meets the most rigid quality standards. Specifications for Radian Weapons Model 1 AR-15 6mm ARC 14.5in Upper Receiver: Manufacturer: Radian Weapons Caliber: 6mm ARC Barrel Length: 14.5 in Gas System Length: Mid Length Threads per Inch: 5/8x24 Finish: Nitride Color: Black Fabric/Material: 7075-T6 Aluminum Gun Rail: M-LOK Gun Type: Rifle Gun Make: AR Platform Gun Model: AR-15 Barrel Material: 416R Stainless Steel Bolt Carrier Group Included: MIL-SPEC Charging Handle Included: MIL-SPEC Features of Radian Weapons Model 1 AR-15 6mm ARC 14.5in Upper Receiver Sub-MOA Accuracy Guarantee w/ Black Hills Match Grade Ammunition Billet Machined 7075-T6 Upper Receiver w/ M4 Feed Ramps Proprietary Extended Aluminum Hand Guard w/ Magpul M-LOK Modular Mounting System and Integrated Upper/Hand Guard Stainless Steel Anti-Rotation Pin Enhanced Black Nitride M16 Bolt Carrier Group Lightweight Forward Assist Radian Raptor-SD Suppressor-Optimized Ambidextrous Charging Handle Direct Impingement Gas System Package Contents: Radian Weapons Model 1 AR-15 6mm ARC 14.5in Upper Receiver What firearm models does the manufacturer say Radian Weapons Model 1 AR-15 6mm ARC 14.5in Upper Receiver is compatible with? The manufacturer says that Radian Weapons Model 1 AR-15 6mm ARC 14.5in Upper Receiver is compatible with AR-15Radian Weapons R0898: Model 1 AR-15 6mm 14.5in ARC Upper Receiver Mid Length 5/8x24 Nitride Black