Shimano STEPS RD-M8150-12 Deore XT Rear Derailleur – SGS 12-Speed Top Normal Shadow Plus Direct Attachment. The all-new DEORE XT RD-M8150 speed rear derailleur combines race-proven quality with Shimano original technologies to help keep you flowing and focused on the right line. The new E-MTB optimized design allows full integration with SHIMANO E-Bike Systems and HYPERGLIDE+ drivetrains to unlock entirely new functionality. This system integration allows innovative features like FREE SHIFT. Its a simpler more pure E-MTB experience only possible through the fusion of drivetrain engineering e-bike system components and electronic shifting intelligence.