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. It is important to 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 on. Wolf Tooth Post to Flat Mount Brake Adapters are CNC machined with 6061-T6 aluminum.Specifications:- Material: 6061-T6 Aluminum- Weight: 17gCompatibility: - 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