Manual Threading Pipe and Bolt Die Head Complete w Dies, 1 in 11 1 2 NPT, 12 R, HS, Alloy RH no checkout Split bite jaw increases grip Split bite jaw increases grip over standard bite chucks by providing more contact with the bit Superior gripping force provides high mechanical advantage to convert hand tightening torque into superior bit gripping force Hammerlock® mechanism is a positive locking mechanism that prevents loosening in hammer and other high vibration applications Anti lock nut prevents chuck from lock opening Precision operation that meet or exceed stringent din run out and dimensional specifications 1 standards when used with any Jackson Safety brand head gear All die heads complete come with selected dies and are set at the factory Precision threading