Home » headsets » Threadless Headsets » y90a-1 THREADLESS HEADSETS Y90A-1 EC29/25.4 | EC29/27 EC30/25.4 | EC29/26 Alloy Cap/Cup Sealed Bearings Top Nut: 1″ Cup O.D.: 30/30.2 Crown Cone: 27/26.4 Height: 28.8 Technical Diagram