AP Racing PRF660 Competition Brake & Clutch Fluid. Family No. CP4660 AP Racing PRF 660 has been developed for use in extreme high temperature racing conditions: ‘Typical’ New Dry Boiling Point is 320°C. ‘Wet’ E.R. (Equilibrium Reflux) Boiling Point is 199°C (390°F). AP Racing PRF660 Fluid Conforms to and exceeds U.S. FMVSS No 116 DOT 4, SAE J1703 and SAE J1704 specifications and has been developed for racing applications where higher than normal temperatures are being experienced, e.g. when using carbon / carbon discs and the ultimate in brake fluid performance is required. It should be noted that before using AP Racing PRF660 fluid, any existing brake fluid should be drained completely from the brake system. The system should be thoroughly purged with new AP Racing PRF660 brake fluid and can then be filled completely with AP Racing Racing 660 fluid. IMPORTANT NOTE DO NOT USE AP Racing PRF660 fluid in contact with any type of magnesium components (e.g. gearbox / clutch components) as a chemical reaction is caused resulting in gases being generated. This will then prevent the clutch hydraulics from working efficiently. DELIVERY is EXTRA! Price is per litre (available in 0.5 litre quantities).