Extract every ounce of cooling efficiency from Koyorad All Aluminum Performance Radiators with a genuine Koyorad Hyper Cap! This Koyorad Hyper Cap withstands an increased valve pressure rating of 1.3kgf/cm2 (1.3 bar) (18.9 psi) (130 kPa) which increases the boiling point of water and relieves high performance engines of excessive heat. A genuine Koyorad Hyper Cap is recommended for use with every Koyorad All Aluminum Performance Radiator (when applicable). This Koyorad Hyper Cap is manufactured in Japan from high quality components to ensure longevity and performance from your Koyorad Racing radiator.