Top hat design for mounting links above the differential. This design allows for double triangulation of your 4-link Rockwell axle. Our design does NOT use the 3/8" inspection cover bolts of other designs. Instead, we incorporate 12 of the 1/2" bolts on the bearing flanges. Underside gusseting adds further strength and rigidity. Sold as a weld together kit with top plate of 5/16" steel and 3/8" steel side plates. Generous flat area of 11 3/8" by 14" for the standard rear NONSTEERING axle. Front and rear designs integrate the Wilwood caliper and Mazda rotor pinion brake. Mazda rotor bore must be machined larger and redrilled to fit the Rockwell pinion flange. Machined rotor available. Link tabs NOT included. Please contact us for any questions.