Modular hubs with a variety of axle conversion options. Forged, CNC machined 6061 aluminum shell, sealed cartridge bearings. Two row sealed looseball bearing freehub body, 8/9sp HG compatible. Integrated 3 pawl positive engagement drive. International Standard 6-bolt disc rotor mount . Front: includes convertible endcaps to switch between 9x100mm QR or 20x110mm thru-axle. 215g/475g (stub axle options allow front to convert to nutted 3/8" or 14mm fixing see Halo adapters) . 2007 Saint derailleur compatible axle sold separately (BTI #HL-3154), also M10 solid (HL-3158) and M14 adapters (HL-3156). Spin Doctor hubs also sold in Halo Combat, SAS, Tornado, Freedom wheelsets see BTI wheels