Brake pressure was transmited by brake fluid, the pressure transmit will out of function once brake fluid include too much water. suitable for safe-driving, we must test water ratio scale in brake fluid regularly. Brake fluid tester help us do current maintenance, make sure we drive in safety condition. Brake fluid tester with 250mm goose neck probe provides flexibility of detection, Chromed detector resistant to oils and oxidation; 2.2 inch LCD display with backlit provide intuitive interface Hand-held size provide one hand operation experience Buzzing and red light double alarm system, test result is clear absolutely, Universal fit suitable for most vehicle. High precision to test DOT-3, DOT-4, DOT-5 brake fluid. How To Use:1. Install one 9V(6F22) battery at the back of tester.(battery not included) 2. After inserting the battery, press POWER button to turn on the tester, all lights turn on with buzzer sounding, 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 . 5. According to results to find out the status of brake fluid. Colour:Black+Green Material:ABS Package Contents: 1 x brake fluid tester Note: 1. After use, please clean the probe and avoid any retention of stains that might affect the test. 2. If in use suitable for a long time, best to remove all batteries and store in a dry place at normal room temperature. Only the above package content, other products are not included. Note: Light and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.