Overview This system features the 4-piston, S4 caliper mounted to a 13", 2 piece slot, drill, zinc-plated rotor. The S4 caliper has D.O.T compliant dust and weather seals and uses the popular DR1-C pad type. Rotors are pre-assembled with NAS high grade stainless hardware. Baer’s unique backing plate not only acts as a caliper mount, but also houses a modern 1-piece park brake shoe assembly. Stainless braided hoses and hardware are also included. The 13" SS4+ fits most 17” or larger wheels. Features 2-Piece, 4-Piston, S4 Caliper Manufactured in Phoenix, AZ CNC Machined from US Sourced Forged or Billet Aluminum Powder Coated Finish Hard Anodized Aluminum Pistons, Stainless Steel Abutments and Noise Suppression Clips Dual Seals, Dust/Weather & Pressure 2-Piece Slot, Drilled, Zinc-Plate Rotor w/Billet Aluminum Hat