Just when you think you had headsets figured out, the industry decided to throw a curve ball, actually a few curve balls and offer several options by offering large head tubes and tapered forks. The FSA Orbit ZS is made to work with a frameset that has a 1.5" head tube diameter that is being used with a tapered fork - tapered meaning 1.5" lower section of the steerer which tapers to 1 1/8" diameter.
The upper portion of the headset has an 1 1/8" forged alloy cup with angular contact bearings, while the lower portion has a 1.5" CNC machined alloy cup with angular contact bearings. Alloy top cap is included. Total weight comes in a respectable 144 grams and is offered in anodized black finish.