Castrol SRF Brake Fluid's unique silicon ester technology absorbs less water than conventional glycol ether fluids and prevents the fluid's high temperature performance from deteriorating. Its wet boiling point of 270°C is vastly superior to the minimum requirement of 155°C demanded by the current US DOT 4 specification. Its ability to withstand temperatures in excess of 300°C 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.