SP 7 Series Dynamo Front Hub - PL-7 6V 3W 12 x 100mm Centerlock 32H BlackSP 7 Series Dynamo Front Hub PL 7 6V 3W 12 x 100mm Centerlock 32H Black. The 7 series dynamo hubs are a bold advance in innovation and technology matching the output of the 8X series with a reduced weight of 60 grams. Compatible with standard dynamo system lights and convertors for USB powered devices while providing a slightly higher output than 8 and 8X series hubs. High quality sealed bearings and assembly processes TECH SPECS Bearing Type Sealed