Park Tool 2197 Diamond Abrasive Adaptor for Carbon FiberCompatible with post mount and flat mount disc brake mounts NOTE: The 2197 is intended for facing carbon fiber only. Aluminum, steel, and titanium disc brake mounts should be faced using the #2171 facing cutter included with the DT 5. 2. For carbon frames that feature aluminum inserts (with a carbon aluminum hybrid mounting surface), use the #2197. When machining carbon fiber, regularly apply water (or a similar solution) to the cutting surface.