The Shimano Nexus 3R40 hub offers a reliable 3-speed mechanism, Silent Clutch and roller brake. Note: comes without cap nuts Specifications: Color: silver, black Group: Nexus Type: Rear hub Shimano Code: SG3R40 Type of Bike: City bike Brake: Rollerbrake Number of gears: 3 Material: Steel Number of spoke holes: 36 Axle Length: 170 mm Mounting width: 111 mm Weight: 890 grams