FOR HOLDING YOUR WHEEL TOGETHER - THE SPECIALIZED FREEHUB FORMULA MY13 BODY.To take your bike to the next level, use The Specialized Freehub Formula My13 Body. it's sleek design and simple installation will make you the prize of the biking world. FEATURESBody compatible with rear hubs Formula 142, 142+ 148 (Boost) mmCompatible with: Camber / Enduro / Epic / Stumpjumper FSR Comp and all other models with Formula hubsTECH SPECSAluminum axis length: 132 mm