Aluminum crown race for 1" Full Speed Ahead Duron X and Orbit X headsets.

26.4 mm crown race ID

Since the crown race for the FSA Duron headset is lightweight aluminum, it is not reusable if you have to take it off (unlike steel headsets that are heavier but less prone to getting damaged if you have to take them off).  So, get your replacement FSA Duron/Orbit crown race here.