stainless steel, Angular Contact, External Bearing Kit for 34mm (1-1/8″”) ID head tube framesets This unique bearing kit eliminates the external headset bearing cup and provides a simple low profile solution where the bearing itself presses directly into the head tube. The kit includes fork crown race and upper split-ring and cap. Not all stainless steel is created equal. Enduro only uses 440C stainless steel balls and races to provide long life and superior corrosion resistance in applications and environments that may be less than ideal. 440C has the highest strength, hardness, and wear resistance of all the standard 440-series stainless alloys with high carbon content.