Circuit Hero high pressure radiator cap uses a 1.3 Kgf/cm² spring to increase your coolant/antifreeze boiling point and protect your engine. An added bonus we've incorporated is the built-in button valve. To ensure there is no hot heat pressure built up, always press the button to make sure there is no hot vapors in your radiator before opening the cap.  Pressing the button also allows hot vapors to escape for quicker cooling. *NEVER OPEN RADIATOR CAP WHEN HOT. Features High pressure spring to raising engine boiling point. Safety button to reduce chance of being burned. Release hot vapors to cool down engine faster. TYPE-A VEHICLE APPLICATIONS Fits most aftermarket radiators Fits Blox Racing Radiators1988-1991 Honda Civic1988-1991 Honda CRX1992-2001 Honda Prelude2016+ Honda Civic 1.5T2017+ Honda Civic Type-R1990-1993 Acura Integra2003-2007 Mitsubishi Evolution VIII, IX2008+ Mitsubishi Evolution X2002+ Subaru WRX, STi