This system showcases the impressive S4 4-piston caliper, perfectly paired with a 12-inch, one-piece slotted and drilled zinc-plated rotor. The S4 caliper comes equipped with D.O.T compliant dust and weather seals, and it accommodates the widely-used DR1 or HB100 pad types. What’s really cool about Baer's design is that their unique backing plate not only serves as a caliper mount but also houses a modern one-piece park brake shoe assembly. You’ll also appreciate the included stainless braided hoses, which add to the overall quality of the setup. The 12-inch SS4 is compatible with most wheels that are 16 inches or larger. This system fits rear ends with GM small pattern 10/12 bolt bearings on the axle (BOA) and has flush mount bearing housing ends, accommodating both 5x4.75" and 5x5" bolt patterns.