Internal gear 3-speed hub: for use with any IS 6-bolt disc brake . Rotary gear selection with no protruding indicator chain or switch box . 6061 aluminum hub shell with 13/32" slotted solid axle (215mm overall axle length) . Gear ratio range of 177% (33% each step) . Includes 3-spline 18 tooth cog and a SLS30-T twist shifterItem Specifications: Number of Holes: 36, Front or Rear?: Rear (3sp), Color: Black, Model Name: RS-RK3, Rear Axle Spacing: 13/32"x135 Nutted, Spoke: J-Bend, Brake Type: 6-Bolt, Weight: 1000g,