Cannondale Scalpel Si X12 142mm Rear Derailleur Hanger is compatible with bikes with X12 axles with 142mm such as the Cannondale Scalpel Si. The axle threads into the derailleur hanger for a perfect fit. Not compatible with Maxxle style axles. Kit includes one hanger and one mounting bolt.Details:

•  Compatible with X12 axles with 142mm such as the Cannondale Scalpel Si
•  Axle Threads into the Derailleur Hanger for a perfect fit
•  Not Compatible with Maxxle style axles
•  Kit includes one hanger and one mounting bolt