Handy tool aids in applying straight-line torque for fast, easy installation of the AR 308/AR-10 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 ½” square drive.