DUOYI DY23B Car Brake Fluid Detection Pen Moisture Tester 1. Brake pressure was transmitted by brake fluid, the pressure transmission will out of function once brake fluid including too much water. In order to safe-driving, we must test water ratio scale in brake fluid regularly. The brake fluid tester help us do current maintenance, make sure we drive in safety condition. 2. HD backlight dual display, support backlight display glare and easy reading day and night. 3. Operation Manual: (1). Install one 9V(6F22) battery at the back of tester.(not included) (2). After inserting the battery, press POWER button to turn on the tester, all LEDs lights turn on with buzzer sounding, which indicates the product self-test is successful. (3). Press SELECT button, it will locate DOT3 model automatically. (4). Each time you push the SELECT button, it will recycle from DOT3 to DOT4 to DOT5.1 with the indicator LEDs. (5). Immerse the probe into brake fluid and you will get different colors of LED lights, they indicate: Green Light: indicates the brake fluid water content is below 1% The First Yellow Light: indicates the brake fluid water content is approximately 1.5% The Second Yellow Light: indicates the brake fluid water content is approximately 2.5% The First Red Light: indicates the brake fluid water content is approximately 3% The Second Red Light: indicates the brake fluid water content is more than 4% (6). Press POWER button to turn off the tester. 4. Note: (1). After use, please clean the probe and avoid any retention of stains that might affect the test. (2). If in use for a long time, best to remove all batteries and store in a dry place at normal room temperature. 5. Package include: Brake fluid tester x 1 User manual x 1