This system features the S4TL 4-piston caliper mounted to a 11", 1 piece slot, drill, zinc plated rotor. The S4TL caliper has D.O.T compliant dust and weather seals and a banjo type inlet, no pipe threads. Baer’s unique backing plate not only acts as a caliper mount, but also houses a small, more compact park brake assembly for improved wheel fitment. Stainless braided hoses and hardware are also included. The 11” SS4 fits most 15” or larger wheels.