If you own a Pinarello Prince Carbon, Dogma FPX, or Dogma FP, these are the replacement cartridge bearings for your headset. Since no other headset system is compatible with your Pinarello, this is exactly what you need if your headset starts to feel grainy after a few years of riding. Sweat takes its toll on cartridge bearings, so this is a normal piece of maintenance for your bike after about 10,000-20,000km. You get two bearings, one of which is 1-1/4", and the other 1-1/8". Not compatible with any other Pinarello frame model except for Prince Carbon, Dogma FPX, and Dogma FP.