Mesa Tactical Mesatac AR-15 Torque Rod Black. The Torque Rod features 5 flat sides designed to be gripped in your bench vise. With the Torque Rod secured slide your AR-15s upper receiver over the opposite end of the Torque Rod. The Torque Rods eight splines mesh with the locking lugs of your barrel extension in your upper receiver. The torque applied to your barrel nut or muzzle devise is then transferred to the Torque Rod in the vise. Using a Torque Rod instead of a clamshell style vise block will prevent twisting damage to your upper receiver or marring of your receivers finish. Torque Rods are an essential tool for billet AR-15 upper receivers that do not fit in clamshell style vise blocks. Specifications for Mesa Tactical Mesatac AR-15 Torque Rod: Manufacturer: Mesa Tactical Gun Model: AR-15 Fabric/Material: Steel Color: Black Features of Mesa Tactical AR-15 Vise Mount Style Torque Rod Easy installation and removal of barrels muzzle devices gas blocks and handguards Prevents damage and marring of upper receiver Works with billet AR-15 upper receivers Heavy-duty solid steel with attractive black oxide finish 12 and 5/8 overall length with 5 vise flats Package Contents: Mesa Tactical AR-15 Vise Mount Style Torque Rod includes necessary hardware What firearm models does the manufacturer say Mesa Tactical Mesatac AR-15 Torque Rod is compatible with? The manufacturer says that Mesa Tactical Mesatac AR-15 Torque Rod is compatible with AR-15Mesa Tactical 90510: Mesatac AR-15 Torque Rod Black