Convert your ISO 6-Bolt (non-Boost) hubs to fit Shimano HG, Micro Spline, or SRAM XD cassettes using our latest technology. This latest update to our hubs uses a Gen 4 142x12mm axle, adjusting clamp, and a Gen 4 Mountain driver. Gen 4 conversion kits include a pre-assembled axle, driveshell, and adjusting clamp for a plug and play swap. Installation requires a 2.5mm hex key and T10 Torx tool. Twin bearing Stainless steel bearings. Latest Gen4 Internals Compatible with non-boost ISO 6-Bolt hubs, and Universal Disc Hubs. Serial numbers will begin with 161, 162, 910, 911, 912, or 913. 142x12mm axle.