StopTech High Performance Racing Brake Fluid is a DOT 4 motor vehicle brake fluid, engineered to optimize brake system performance at high operating temperatures. In addition to guarding against boiling and subsequent loss of efficiency at severe racing temperatures, StopTech Racing Brake Fluid maintains its excellent viscosity, lubricity and non-compressibility. StopTech High Performance StopTech brake fluid is mixable with all DOT 3 and 4 products but should not be used in vehicles with mineral oil systems.