Park Tool has been manufacturing bike specific tools for over 60 years. In that time, it's had enough feedback from pro and amateur wrenches either requesting or updating tools, that the entire lineup is pretty well refined. Adding to its impressive portfolio of tools are its Metric Wrenches. These 3. 2mm thick wrenches are perfect for when you need to fit in tight spots on derailleurs or brakes. Nickel plating prevents rust and adds durability. Please note that the CBW-1 has 8mm and 10mm open ends and the CBW-4 has 9mm and 11mm open ends.