Highly efficient44 super light weight44 premium grade 6 volt 3 watt dynamo front hub with easy to use quick releaseprovides bright illumination for safer night riding without the need and expense of replacing batteriesimportant weight savings are made by using an efficient and light weight aluminium coil structurefor use with rim brakeslabyrinth and contact sealing as used on the premium dura ace and xtr groupsets low friction seals and internal grease sleeve effectively shut out water