All Balls 19-1016 U-Joint U-Joints are cold forged from SCM-415 steel, precision ground journals are case hardened to HRC58-61 U-Joints are pre-greased with hi-temp lithium complex 3 grease Bearing cups feature a Quad lip seal to keep contamination out & grease in Centrally located grease zero and grease channels in the bearing cup evenly distributes grease Kits include cap plug to eliminate grease zero for low clearance applications