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 is designed with D.O.T compliant dust and weather seals, making it reliable for various conditions, and it works seamlessly with the widely-used DR1 or HB100 pad types. What sets Baer's design apart is its unique backing plate, which not only serves as a caliper mount but also accommodates a modern one-piece park brake shoe assembly for added convenience. Plus, you'll find stainless braided hoses included for durability and performance. The 12-inch SS4 is compatible with most wheels that are 16 inches or larger, making it a versatile choice for many setups. It's designed to fit rear ends with GM Small Pattern 10/12 bolt bearings on the axle (BOA) and flush mount bearing housing ends, with bolt patterns of 5x4.75" and 5x5".