Upgrade for Shimano XTR and XT 12 speed rear derailleursBuilt to offer extremely low friction paired with increased stiffness for loss free shiftingLong tooth profile on lower pulley offers best possible chain retentionLower pulley assembly features a chain catcher to prevent jamsCan be used dependably on or off roadOversized 14 and 18 tooth Kogel pulleysShimano XTR 9100Black