Shimano XTR RD-M972 Rear Derailleur: M972 'Shadow': lower profile body with direct cable routing, stronger spring, and redesigned bracket to avoid chainstay contact (carbon cage and aluminum B-attachment with a Top-Normal return spring). Wide link parallelogram design increases rigidity and performance. P-body rubber bumper reduces noise and adds durability (M971/970). 4 fluoric coated link pivot bushings minimize friction. Aluminum construction with sealed bearing 11-tooth pulleys.