Excellent quality & durable 6 volt 3 watt dynamo front hub with low rolling resistance & easy to use quick release Provides bright illumination for safer night riding without the need & expense of replacing batteries For use with rim brakes Features contact seals to prevent the ingress of corrosion-causing water & muck without affecting rotational smoothness increasing service life High quality bearing races reduce friction & provide a more precise bearing action Push-in wiring harnesses make installation fast & easy Forged aluminium hub shell Comes with an easy to use quick release skewer 74 mm O.L.D