Cane Creek Headset Service Parts. Features: Crown races, compression rings and bearings for servicing Cane Creek headsets (see Aheadset for other parts) * Upper and lower replacement bearings sold as a set for tapered fork headset applications ** AER series bearings are cross-compatible across the line, using aluminum and steel construction, 35% lighter than 110 and 40 series bearings 40-series crown races are cross compatible with all series headsets Specs: Fits Model:black oxide bearing (41/52mm) Size:36x45 degree tapered Package:upper/lower set*