Stable performance of the drive on trails, gravel paths, and city streets. The chain stabilizer reduces chain jumping, 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 that this versatile 1x11-speed rear system offers. Its compact design and chain stabilization system give riders the confidence they need to choose hillier routes.