- 12 mm hex wrench
The Park Tool HR-12 is a simple 12 millimeter hex wrench, constructed from through-hardened industrial-quality steel with chamfered tips for a precision fit. 12 mm hex wrenches are sometimes necessary for removing the freehub bodies from several popular brands of hubs (Mavic®, Shimano®, Sun Race®, Sovos™, and others). Also sometimes used for thru axle hub service.