Fsa orbit 15 zs headset no 57 1full speed ahead fsa produces world class bicycle components for road cycling mtb and triathlon for world tour teams club riders and people who just love to ride their bikes fsa has a long history in the sport of cycling and a strong heritage of innovation in design and manufacturing features 1 18 36 45 acb1 18 steererupper headtube 44mm idlower headtube 56mm idalloy top coverforged alloy shallow cupsangular contact bearings blue sealstack height