Castrol SRF is the ultimate racing brake fluid. Its unique silicon ester technology absorbs less water than conventional glycol ether fluids and prevents the fluid's high-temperature performance from deteriorating. It's high boiling point, ability to withstand extreme temperatures and superior resistance to the effects of absorbed water have established Castrol SRF Brake Fluid as the world's premier fluid for the hydraulic brakes used in all forms of motorsport and racing.