This system features the 4-piston, S4 caliper mounted to a 11.62″ x .705″ 2 piece slot, drill, zinc plated rotor and uses the popular HB540 pad type. Rotors are pre-assembled with NAS high grade stainless hardware. Mounting hardware is also included. This SS4 Deep Stage system is the lightest weight version available, and is recommended for use with parachutes, and/or lighter weight vehicles.  If you have a full weight S550, and rely more on brake alone the version 2.0 is recommended. NOTE: This system comes equipped with a street compound pad that offers low noise and dust and are NOT suited for track use. Race compound pads are also available for track use, call for information. Drag Race systems come standard in Clear and Fire Red caliper colors. | Rotor Size/Type: 11.625″ x .705″, 2-piece | Replacement Rotor Rings: 6910186 (Left) / 6920186 (Right) | Caliper/Piston Count/Mount Type: S4 / 4-piston / Lug | Replacement Pads: 6070012 (Street) 6070012-S (Race)   | Minimum Wheel Size: 15″ (Use template to verify fitment, link below) | System Includes: Calipers, Brake pads, 2pc rotors, Banjo bolts & washers (does not include hoses) | Notes: Designed to be used with 2015-2018 Ford Mustang S550 Front Spindles.  System weight – 28.1lbs https://www.baer.com/templates/S110I.pdf fhttps://baer.com/site_images/Brake_System_Fitament.pdf