This Shimano SM-AD91 Dura-Ace 9150 Di2 front derailleur band adapter is designed to fit a braze-on derailleur to a band-on frame. It is compatible with the FD9150 derailleur and is available in black with a 34.9 mm size. This adapter is suitable for Road, Time Trial, and Triathlon disciplines and supports 11-speed and Di2 systems.