DISC BRAKE FRAME ADAPTOR
There are three type of disc brake adapter:
Short (with clamp 15-25mm)
Long (with clamp 15-25mm) <-- This adapter is universal, if you are not sure about the option, please choose this. This can be fit on most bike.
Long (with clamp 25-35mm) <-- This adapter has a larger clamp which allows it to be fit on mountain bike with larger frame diameter.