The Wolf Tooth Post to Flat Mount Brake Adapter allows you to install flatmount brakes on a frame or fork that has been designed for post mount brakes. An important component for cyclists who want to run a road set on a mountain bike frame. It's important to note that this is a +20mm adapter, which means that the brake size for a 140mm disc will only work with a 160mm disc, just as a 160mm caliper will only work with a 180mm disc, and so on. Wolf Tooth Post to Flat Mount Brake adapters are CNC machined from 6061-T6 aluminum. They are sold individually. Compatibility : Fits on post mount native sizes 140, 160, and 180mm Works with rotor sizes 160, 180, and 200mm Tested with SRAM and Shimano brakes Requires minimum 13mm between top of brake boss to frame/fork Includes (2x) M5x13mm flat head bolts for flat mount caliper and (2x) M6x15mm socket head bolts for post mount Weight : 17g Material : 6061-T6 Aluminum