The Industry Nine Hydra Classic ISO 6B Super Boost XD Rear Hub turns heads with its distinctive near-700-clicks-per-revolution sound that announces your presence on every trail. That signature buzz comes from revolutionary 0.52° engagement that provides virtually instant power transfer when you need it most on technical climbs or quick accelerations. Machined from 7075-T6 aluminum, these hubs combine bomber durability with surprisingly low weight, while the intuitive design lets you service them without proprietary tools. This model uses Super Boost spacing and is compatible with SRAM XD cassettes. Bzzzzzzzzz.