The approved method of testing the water content of brake fluid. Just 3% of moisture can lower the brake fluid boiling point by over 100°C. The best way to detect this small water content is to measure the boiling point of the fluid. The unit incorporates a heater element, LCD display and a power lead for use on 12V DC power supplies. Works on DOT 3, 4, 5 and 5.1 specification fluids. Supplied in storage case with full operating instructions.