Home » headsets » internal cable routing » c550a Semi-internal Cable Routing Headset Installation INTERNAL CABLE ROUTING HEADSET C550A WATERPROOF ZS56/28.6 | ZS56/40 Alloy, Sealed Bearings 1-1/8″ to 1.5″ Tapered Steerer Top Nut: 1-1/8″ Cup O.D.: 56 Crown Cone: 39.8 Height: 11.5 Weight: 158g Technical Diagram