After testing,please clean the liquid on the tester pen with a dry cloth or paper,otherwise the pen will easy to corrosion !!! Warm tips: 1. Please replace battery if the green LED not light up any longer after you press power on button. Wash the test probe with tab water after use. 2. In case of skin contact with brake fluid, please wash the affected skin or clothing with water thoroughly. 3. Do not expose brake fluid to the atmosphere for a long time as the fluid is highly hygroscopic. 4.Auto power off, Supports 1 LR03 AAA battery (not included) Features: 1. Available for automatical power off. 2. Operated by a 1.5V "AAA" battery (not included). 3. with five LED indicators for accurate testing results. 4. Widely used for testing DOT 3, DOT4 and DOT5 brake fluid. Specifications: Item Type: Brake Fluid Tester Material: Plastic Color: Black Detection System: Brake Fluid Voltage: 5 Working Temperature: -20-80 Size: 15*2.5*2cm Flashing Instructions: 1. The green LED lights: water content in the brake fluid H2O <1.5%, brake fluid qualified 2. The yellow LED lights: brake fluid water content H2O = 1.5% to 3%, can continue to use, test again six months later 3. The red LED lights: water content in the brake fluid H2O> 3%, can not continue to use the brake fluid needs to be replaced Red LED: change brake fluid 4. LED red flashing: battery replacement 5. LED yellow flashing: low moisture content, check again in six months 6. LED green flashing: brake fluid lines/cell row Technical parameters: Green: Battery is normal and the brake fluid does not contain water Green/yellow: brake oil in water content of less than 1%, better brake fluid performance, ease of use. Green/yellow/yellow: brake oil in water content of about 2%, brake fluid can continue to use. Green/yellow/yellow/red: brake oil in water content of about 3%, the proposed replacement of brake fluid. Green/yellow/yellow/red/red: brake oil in water content of at least 4%, the brake fluid must be replaced immediately responsible for very dangerous. Package Includes: 1Pcx Car Brake Liquid Testing Tool（No Battery）