Today's increased water pressure and temperatures require a better seal than stock oil caps can provide. That's why CV4 worked with professional engine builders to develop these new higher pressure radiator caps. High pressure radiator cap designed for modern racing 4-stroke engines. Allows running a higher water system pressure and higher boiling point coolant. Fits most O.E. and aftermarket radiators used on most Japanese models. Rated for 1.4 Bar / 20 PSI. Sold individually. Note: Will NOT work with KTM, Husaberg, or Husqvarna bikes or ATVs.