Neco H373S 1-1/8" to 1.5" Tapered Fork Tube & 42-52.2mm Head Tube MTB Bike Bearing Headset Use for 1-1/8" Tapered to 1.5" Fork Tube Headtube ID.: 42mm-52.2mm Crown Race: 39.8mm SHIS NORM: IS42/28.6 | IS52.2/39.8