Race Face Vault Rear Hub Race Face's new Vault Rear Hub performs exceedingly well in a range of conditions. It offers super-fast engagement and comes in Boost and Non-Boost sizes. There are options for SRAM XD or Shimano HG drivetrains, making it an awesome choice for bikes of all kinds. The 6902 bearings are large-diameter and give you smooth, reliable action. The 60-tooth ring uses 6 double-tooth pawls that offer 3-degree engagement for super snappy acceleration. Also, the endcaps were designed with tool-free removal so you can alternate between axle types. Features Axle size: 12x142mm, 12x148mm, 12x150mm Drivetrain compatibility Shimano HG or SRAM XDSpoke count 28 or 32H | Race Face | Vault Rear Hub 12X148Mm Boost, 32 Hole, Sram Xd Driver