NECO H373C Carbon Fiber 1.5" Head Tube Recuced to 1-1/8" Fork Tube MTB Bike Headset 42-52.2mm Headtube &hellip; Carbon Fiber Top Cap & Top Cover Use for 1-1/8" to 1.5" Tapered Fork Tube Headtube ID.: 42-52.2mm Crown Race: 39.8mm SHIS NORM: IS42/28.6 | IS52.2/39.8