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 hammer 1 18 headset is a conventional threadless headset that has been forged and cnc machined from steel to make a headset that is for heavy duty use this 1 18 headset uses 532 caged ball bearings on the upper and oversized 316 on the lower