Handy tool aids in applying straight-line torque for fast, easy installation of the barrel nut without scratching the exterior of the upper receiver. Helps ensure the right amount of torque is evenly applied, while maintaining proper alignment of the barrel, upper receiver, and gas tube ports. Use with any barrel nut wrench or free-float tube wrench and a torque wrench with a A 1/2" square drive. Simply clamp the barrel nut wrench handle firmly in a bench vise, insert the barrel into the upper receiver, and finger tighten the barrel nut. Slide the barrel through the wrench, insert the Torque Tool in the back of the receiver until the teeth lock into the locking lugs in the barrel Mfg: Brownells SPECS: Machined steel, black oxide finish. 10" (25.4cm) long, 1.18" (3cm) diameter. Requires a A 1/2" square drive torque wrench. Instructions included. Fits .308 DPMS pattern uppers/barrel extensions EXCEPT the new G2 versions.