It is a 14 mm rear hub. La bolt screw out the screw in the socket or hex 6 mm 17 mm fixed hub bearings so sealed bearing four of your strength. It is a hub also ball friction, rolling good. Shell with 7075 aluminum material so to which you do not.
For the rear of unit sales.
Color: M.Black Shell: New 7075 Aluminium Shell Design Chromoly Axle 14 mm Number of holes: 32 H, 36 H Bearings: 4 pc Sealed Bearings