Use: Road Group: Dura Ace Di2 R9250 Model: RD-R9250 Mount type: Direct Mount Gear rear: 12-speed Compatible chain: CN-M9100 HG 12-speed Max. teeth large sprocket: 34T Min. teeth large sprocket: 28T Max. teeth small sprocket: 11T Min. teeth small sprocket: 11T Max. front difference: 16T Total capacity: 35T Compatible electric wire: EW-SD300 Firmware update by E-tube Project: Yes E-tube port (pcs): 1 E-tube connector (pcs): 0 Di2 Wireless-Chip: Yes