While most companies now days are expanding their drivetrains upwards of 13 speeds, Box believes that more is not necessarily better. The Idea behind the 9-speed drivetrain is to keep things simple while receiving the same gear range in a more efficient package; resulting in less shifting error, which produces a more user friendly experience. Features: Wide range 9 speed single-shift group for use with e-bikes Simple durable performance without all the bells and whistles Includes E-bike optimized 12-50t cassette, rear derailleur, shifter and chain Single shift per swing for E-Bike safe shifting Wide ratio with consistent progression Glass fiber / nylon composite, steel and aluminum construction Includes: Cassette (12-50T) Rear Derailleur Shifter Chain Specifications: Cassette Body Type: Shimano/SRAM (Not Compatible with XD or MicroSpline) Rear Derailleur Speeds: 9-Speed Rear Derailleur Max Cog: 50T Rear Derailleur/Shift Compatibility: Box Prime 9 Shifter Style: Thumb Shifter Speeds: 9-Speed Single-Shift Color: Black