Optimized for impact survivability, the 12-speed mid-cage M9250 rear derailleur is the choice for both Shimano's top enduro athletes and weight-conscious XC racers alike, especially when matched with the 9-45 compact cassette. Featuring all-new wireless Di2 shifting, Automatic Impact Recovery, a redesigned wedge shape and 23 mm of additional ground clearance for a bash-free ride, this rear derailleur stands out for the speed of its shift and its ability to keep riders competitive on the trail. FEATURES: Robust Design: A wide link structure, skid-plate design, durable carbon plate and solid pulley add robustness and longevity. RD Protection Function: The new Automatic Impact Recovery function instantly returns the derailleur to its original position after impact. SHIMANO SHADOW ES: A slimmer, stronger evolution of Shimano’s pioneering chain-stabilizing SHADOW concept. Precise & Clean Wireless Shifting: Wireless Di2 paired with HYPERGLIDE+ technology result in smooth, precise and instantaneous shifting Wedge Shape: The new wedge shape of Shimano’s most survivable rear derailleur to-date avoids more direct impacts, and smoothly glances off rocks if there is a hit. Protected Battery: Tucked safely inside an enclosed space, the battery won’t budge even in rough terrain, while remaining completely removable for charging. SPECS: Cage Length: GS or SGS Total Capacity: 36T (GS) or 41T (SGS) Color: Series Color Mount: Direct attachment (conventional) Guide Pulley Bearing: Sealed Bearing Tension Pulley Bearing: Sealed Bearing Series: XTR Generation: M9200 Max Low Sprocket: 45T (GS) or 51T (SGS) Min Low Sprocket: 9T (GS) or 10T (SGS) Rear Speeds: 12 Top Normal Spring Type: Shimano Shadow RD+