The AP Racing PRF 660 brake fluid has been re-branded as Radi-CAL™ R3 - Silver Bottle with Yellow cap. The AP Racing R3 brake fluid has been developed for use in high temperature racing conditions. AP Racing APR3 Meets DOT4 specification. You need to drain the system of existing fluid before using this fluid. The dry boiling point is 325°C and the wet boiling point is 204°C.