Stable drive performance on trails, gravel paths, and city streets. The chain stabilizer reduces chain skipping, rattling, and noise. The compact profile design is optimized for uneven terrain. Total capacity: 39D. Maximum large sprocket: 50D (1x11 speeds), 48D (1x10 speeds). Designed and tested to provide lasting performance for e-bike riding. Developed specifically for electric bicycles. Tackle the trails with the smooth shifting and pedaling motions offered by this versatile 1x11-speed rear system. Its compact design and chain stabilization system give riders the confidence they need to choose hillier routes.