Wireless Di2 shifting designed for E-MTB and HYPERGLIDE+. The ultra-durable RD-M8260 long-cage rear derailleur delivers features all riders can appreciate. It taps into proven wireless Di2 shifting technology and the strengths of other XT offerings while pulling power from the bike&';s main battery delivering a stable power supply and eliminating the need for a back-up battery.Direct Wired: The derailleur pulls power from your existing e-bike battery to deliver a constant supply of shiftsA wide link structure skid-plate design durable aluminum plate and solid pulley add robustness and longevitySHADOW ES: A slimmer stronger evolution of SHIMANO&';s pioneering chain-stabilizing SHADOW RD+ conceptE-Bike Technology: Intelligent AUTO SHIFT sensors and HYPERGLIDE+ technology provide smooth quick gear changes while you pedal so you are always in the right gearFREE SHIFT E-Bike Technology: Keep your speed and shift whenever. FREE SHIFT technology allows you to shift as you coast on flats or downhills TECH SPECS table{border-collapse:collapse;width:100%;} td{text-align:left;padding:8px;font-weight:350;} tr:nth-child(even){background-color:#f2f2f2} th{background-color:#eb212e;color:white;text-align:left;padding:8px;} .desc .specs-heading{font-size:24px;font-weight:600;padding-top:35px;border-top:3px solid #f0f0f0;display:inline-block;border-bottom:4px solid #eb212e;width:142px;margin:0;} Largest Cog 51 Rear Der/Shifter Compatibility Shimano Mountain Di2 Rear Derailleur Mount Type Shimano Rear Direct Mount Drivetrain Speeds 12 Chain Wrap Capacity (teeth) 41 Cage Length Long Color Black Designed for ebike Yes