Prospeed RS683 Xtreme Performance Brake Fluid Prospeed Extremely high 583 F dry boiling point Very high wet boiling point of 394F Meets DOT 4 specifications and is compatible with all DOT 3, DOT 4, and DOT 5.1 (non-silicone) fluids. Less Compressible than other racing brake fluids allowing for firmer pedal and much better feel and modulation.