The Reichert Optical Brake-Chek® Brake Fluid Tester is a precision optical instrument that is an easy-to-use, accurate, cost-effective tool for determining boiling point and water content of DOT4 brake fluids. With just a couple drops of fluid placed on the sample window, the instrument provides an instant reading. The Brake-Chek® measures the boiling point of the brake fluid and the percentage of water in the brake fluid. The Brake-Chek® is portable with no power cords. It can be used in the service shop or in the field.