The Stranger Ballast rear cassette hub uses the proven internals & driver from the Primo Mix hub for great reliability. The Hub Features a 6061 Aluminium hub shell spinning around a heat treated Crmo axle with precision sealed bearings & a polymer Driver Bearing with 4 Pawls. Comes with primo hub guards. section Product Specs HUB TYPE: Cassette AXLE:14mm Male DRIVER:9t SPOKE HOLES:36h WEIGHT:587g / 20.7oz