Shimano Nexus Rear Hub As a dedicated E-BIKE hub, the Shimano STEPS C7050 series hubs feature a 5-speed range and increased strength and durability for seamless compatibility with mid-ship motors. The Shimano STEPS C7050 hubs add digital precision and integration to Shimano DI2 technology. Specifications: Gender: Unisex Color: Black Material: Aluminum Brake system: Coaster brake Type of bicycle: Electric bicycle Gear ratio: 263% Axle length: 187 mm Flange diameter: 105.2 mm Number of holes: 32 Number of gears: 5 Spoke size: 14 Weight: approx. 2 kg