A bolt-on alternative to our QR axle. Fits a 135x10mm QR or Singlespeed (SSP) one-piece axles on Chris King ISO Rear Hubs (not compatible with 150mm, 157mm Hubs) Allows you to run FunBolts™ instead of a QR Skewer FunBolts™ are 12mm threaded into the axle, with a non threaded 10mm portion. This means that they cannot be unthreaded from the hub with the hub still in the dropout. Doing so can damage your axle or the bolt PHB507-10 for the rear, comes in an assembled pair, includes the bolts, cups, o-rings and thrust washers PHB522 is for a replacement single aluminum cup