Use the Aero Precision AR15 BAR Barrel Nut to install Aero Precision handguards on standard threaded upper receivers. These AR 15 Parts from Aero Precision feature the proprietary BAR interface for secure installation and precise fit of your Aero Precision forends. Aero Precision AR15 Barrel Nuts are machined from billet aluminum and can be installed with a standard AR15 armorer's wrench and an adjustable torque wrench. Install with confidence when you use the Aero Precision AR15 BAR Interface Barrel Nut & Shims. Specifications for Aero Precision AR-15 BAR Barrel Nut and Shims: Manufacturer: Aero Precision Color: Black Gun Model: AR-15 Condition: New Fabric/Material: 7075-T6 Aluminum Quantity: 1 Finish: Anodized Weight: 2.24 oz Country of Origin: USA Features of Aero Precision AR15 BAR-Style Barrel Nut and Shims, 29D-BAN-AR15BRBNSH: Material: Machined from Billet 7075-T6 Aluminum. Coating: Anodized Black. Torque with standard AR15 armorer's wrench (Does not work with Magpul® Armorer's Wrench) Supports Mil-Spec AR-15 barrels with outer diameters up to .998” Package Contents: Aero Precision AR15 BAR Mil-Spec Barrel Nut, 29D-BAN-AR15BRBNSH BAR Barrel Nut BAR Shim Pack (8 shims)