Fsa is the world leading headset manufacturer and the core of their product line with many years of experience they understand that multiple dimensions and exacting requirements are a must when it comes to headsets the fsa orbit uf 1 18 headset is a conventional headset with a 1 18 532 x 22 retainer bearings in the upper cup and 36 x 36d acb in the lower cup the cups are made from a lightweight alloy as well as the top cap which is alloy too it is all sealed in with upper and lower