The Wolf Tooth Post To Flat Mount Brake Adapter allows flat mount brakes to be added to a frame or fork that was designed for post mount brakes. This is a vital component for cyclists who want to run a road groupset on a mountain bike frame.Please note that this is a +20mm adapter which means a 140mm post mount native size will only work with a 160mm rotor just as a 160mm post mount native size will only work with a 180mm rotor and so onFits on post mount native sizes 140 160 and 180mmWorks with rotor sizes 160 180 and 200mmTested with SRAM and Shimano brakesRequires minimum 13mm between top of brake boss to frame/forkCNC Machined from 6061-T6 aluminum for strength and light weightIncludes : (2x) M5x13mm Flat Head bolts for Flat Mount Caliper and (2x) M6x15mm Socket Head bolts for Post Mount