Allows flat mount brakes to be added to a frame or fork that was designed for post mount brakes A vital component for cyclists who want to run a road groupset on a mountain bike frame Adapter adds 20mm so a 140mm post mount native size will only work with a 160mm rotor, a 160mm post mount native size will only work with a 180mm rotor Requires minimum 13mm between top of brake boss to frame/fork Includes: (2x) M5x13mm flat head bolts for Flat Mount Caliper, (2x) M6x15mm Socket Head bolts for Post Mount