Crane HSC Dana 44 outer Knuckles are made from Hi Strength Ductile Iron. They are thicker and heavier where needed for extreme use. The CHC extreme duty interlock system is original to CHC and is designed for use with CHC matching interlocking Hi steer arms. Fits GM, Ford, Dodge, CJ and FSJ axles from 1/4 ton to 3/4 ton. Some applications require caliper bracket, spindle and caliper changes. Link Mount Holes are piloted for ease of install. Installer chooses heims, tie rod ends from 1/4 ton to 1 ton by drilling or reaming to size. It is highly recomended that installation be performed by a Certified 4x4 technician. Crane technical support is available at 303-917-4851. All risks and responsiblities of setting up steering systems are are taken by the installer/purchaser. These knuckles do NOT fit Rubicon TJ or JK D44 axles.