The Industry Nine Hydra Classic ISO CL Boost 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 is for use with SRAM XD cassettes. Bzzzzzzzzz.