machine parts; namely, joints, universal joint shafts, flexible shafts, double joint shafts, hooke's joint shafts, constant velocity joints, cardan joints, double joints, quick disconnect couplings, wobblers, clamping hubs, universal shafts supports, couplings for universal shafts, angular motion couplings, overload clutches, and parts therefor land vehicles and boat parts; namely, joints, universal joint shafts, flexible shafts, double joint shafts, hooke's joint shafts, constant velocity joints, cardan joints, twin cardan joints, quick disconnect couplings, center bearing units and parts therefor; namely, flanges, yokes, bearing units, shifting sections, seals.