Odyssey Pro Headset - Integrated, 1-1/8", 45 x 45, 5mm Stack, BlackThe Pro headset features sealed bearings and a precision tapered wedge to keep the headset tight at all times. High quality sealed bearings Color matched spacers included: 10mm, 3mm and 2mm (15mm total) Laser etched Odyssey bearings Campagnolo standard spec. 1 1 8 integrated headset 45deg tapered bearings 41. 8mm outer diameter (fits 42mm BMX head tubes) Product Specifics Upper Stack Height: 5 S. H. I. S. Stem Clamp Diameter: 28. 6 Threadless Defined