Description: This brake fluid tester is used to determine the moisture according to conductivity change and check the car brake oil quality, it used to test for DOT3 / DOT4 / DOT5 fluid. Features: The main function of this brake fluid test pen is brake fluid quality determining. According to the variation of electrical conductivity to determine the moisture content of the brake fluid change. 5 LED lights display the percentage of moisture content in brake fluid, provides more accurate test result. Designed without cable connector, portable and light weight, convenient to carry and use. Suitable for professional use in automotive repair shops to test DOT3 / DOT4 / DOT5 liquid. Specifications: Condition: 100% brand new Material: plastic, electronic components Color: black Length: approx.155mm / 6.1in Width: 18mm / 0.7in Power Supply: 1.5V LR03 AAA battery (not included) LED: 5 Net Weight: approx.29g Package Weight: approx.61g Package List: 1 * Brake Fluid Tester (Battery Not Included) Instruction: Unscrew the brake fluid reservoir and pull off the cap of the brake fluid tester then dip the test probes into the brake fluid until up to the plastic rim of the device. Product Label Indication: Green: Battery OK,i.e.: No water contained in the brake fluid. Yellow: Less than 1% of water content in the brake fluid. Yellow / yellow: Approx.2% of water content in brake fluid. Yellow / yellow / red: Approx.3% of water content in brake fluid. The brake fluid should be changed. Yellow / yellow / red / red: At least 4% of water content in brake fluid. The brake fluid should be changed urgently! Extreme danger!