Machined from heat-treated domestic materials, our Steel Sprague and Armature plate combo is designed to handle the most extreme applications.This combo is “Bomb Proof”. After years of collaboration with the industry’s leading innovators, we have been able to emphasize and drastically improve every aspect of engagement surface area while in 4WD.Our BOMBPROOF Front Differential rebuild package includes the upgraded 12 Tooth Pre Heated 4130 Steel Sprague cage, 12 Tooth 4130 Armature plate, Billet Spring Retainer, ALL SKF bearings & seals w/ s