Iztor DOT3 DOT4 DOT5 Brake Fluid Tester Vehicle Testing Tool with 5 LED Indicator for Auto Automotive Car Quick and easy way to test for moisture content in the brake fluid; results appear in seconds! LED light indicators show percentage of water in the brake fluid Calibrated for cars using DOT3 DOT4 DOT5 brake fluid Only takes seconds to know the results It determines the quality of brake fluid and measures moisture from 0%-4%.Features LED lights to show moisture percentage. Automatically shuts off after 12 Seconds.1.5V AAA battery included,CE,RoHS approved. Staying safe and knowing that your car is in top condition is most important. Ideally, brake fluid should be checked regularly and changed every one to two years.As moisture seeps into the brake system through the brake hoses and seals the brake fluid will become contaminated and the danger of brake failure will increase.This pen-shaped brake fluid tester can easily help determine whether it&#039;s time for you to change your brake fluid. Remove cap from brake fluid reservoir; Remove probe cap from brake fluid tester; Press power button on top of tester. Green LED lights up; Dip entire length of metal probes into brake fluid; After one second, match color of LEDs with color chart to determine brake fluid quality. Tester automatically powers off after twelve seconds of inactivity. Replace the battery if the green LED light no longer lights up after you press the button. Wash the test probe with tap water after every use. In case of skin contact with brake fluid, thoroughly wash the affected skin or clothing with water. Do not expose brake fluid to the atmosphere for a long time as it is highly hygroscopic. 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.