The Extreme system comes with the 1-piece Monoblock 6-piston, 6S caliper mounted to a 15", 1 piece slot, drill, zinc plated rotor. The 6S caliper is fully machined in Phoenix, AZ from a US sourced 2618 Aluminum forging, includes stainless steel pistons and abutments, D.O.T. compliant dust and weather seals and uses the popular D1247 pad type. All mounting brackets and hardware are also included. The 15” Extreme fits most 19” or larger wheels.