Shimano XTR Rear Derailleur - 12 Speed Gray With Clutch - MediumThe Shimano XTR M9100 is designed to withstand full force pedalling on the roughest trails with smooth shifting and exceptional chain stability. It offers enhanced shifting performance a low profile design and low sprocket compatibility. Designed with a Shadow RD+ clutch to reduce chain slap and create a quiet drivetrain with less distraction Decreased rear derailleur tension at low gear positions prevents high chain tension Features a larger 13 tooth