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 fsas the pig dh pro headset is a conventional threadless headset that has forged and cnc machined alloy upper and cr mo lower cups hold 1 18 3636 degree angular contact bearings the pig dh is designed for heavy duty use of down hill 4x racing and can also take a gyro for bmx