Cyclo: Cyclo Tools dot brake fluid is a premium DOT formulation offering excellent brake performance. It is essential to use the correct fluid in your hydraulic brakes. Not suitable for mineral brake systems. Wide necked bottle enables the syringe to fit right into the bottle, eliminating waste. The fluid will mix safely with other DOT3, 4 and 5.1 brake fluids but is not compatible with 5 silicone based fluid.