This ball center is for use in all RockJock 2" diameter Johnny Joint® rod ends. Ball is CNC machined steel, heat treated, features a 7/16" (.4375") thru bolt hole, a 2" mounting width and is cross drilled for internal greasing of the joint. We use this center in our Johnny Joint® upper control arms for the '97-'06 Jeep TJ and LJ Unlimited.