Brake Oil Fluid Tester LED Moisture Liquid Tool Car Vehicle Test Indicator Pen Description: The main function of this brake fluid test pen is brake fluid quality determining. 5 LED lights display the percentage of moisture content in brake fluid, provides more accurate test result. Brake fluid tester is suitable for determining the quality of brake fluid and escorting your driving safety. The 3-color lighting is intuitive and convenient. Red indicates that the brake fluid needs to be replaced immediately. Green indicates that the brake fluid is in good condition. Yellow indicates that the brake fluid remains good, but it will change. The brake fluid tester determines the change in humidity of the brake fluid based on changes in conductivity. The humidity is clearly indicated by the light-emitting diodes. High levels of moisture will lower the boiling point and then affect the braking performance. Specifications: Color: Black. Size:155mm. Material: plastic. Power supply: 1 AAA battery ( not included ). How to use: Step 1. Turn on the brake fluid tester by pressing the button. A green light should light up. If the light does not come on, it may be time to change a battery. Step 2. Unscrew the lid for the brake fluid reservoir, and take off the cap for the brake fluid tester. Step 3. Dip the test probes into the brake fluid and the LED lights will indicate the percentage of water in the brake fluid. Step 4. After testing, remember to screw the lid of the brake fluid reservoir back on tightly. Step 5. The tester will automatically power off after 12 seconds of inactivity. Package Included: 1 * Brake Fluid Tester(Not Battery Included)