The Shimano Alfine DH-UR705-3D Dynamo hub employs a new internal unit construction that is lighter and also reduces dynamo drag while producing 3 watts. It is designed for 26 to 28-inch Center Lock wheels and uses a 12 x 100mm E-THRU axle design. - New internal unit construction is 28g lighter than DH-T8000-3D - More efficient wheel rotation reduces dynamo drag by up to 44% from DH-T8000 - Proper positioning with 12mm E-THRU - Angular contact bearings - Compact & lightweight - Low rotational resistance - Effortless setting of disc rotor - Durable sealing performance