Feature:How to judge whether the freehub base is suitable for your hub1-The hub ring requires M35 (outer diameter)*10mm height-30 teeth2-for shimano-12-speed3-The outer diameter of the hub is 15mm4-freehub base gears-3 groups 5-ring base diameter 28mm, height 10mmSpecification: Product name: 12-speed-freehubModel: M042-12SMaterial: 7075 aluminum alloy, heat treatmentPawl: hook spring 3PRing: 35(outer diameter)*10(height)mm-30 teethFlywheel: for shimano-12-speedStructure: 2 bearingsProcess: Full CNC cutting, anodizingOthers: Supports 12mm thru-axleWeight: 82.5g Package Included:12-speed-freehub*1