Specification1,check the car brake oil quality2, 5 LED lights display the percentage of moisture content in brake fluid3,auto power off4,Black Brake fluid tester:1 LR03 AAA batteries (not included)Packing list: 1 x brake fluid testerDoes not include battery Instructions:Brake fluid detection pen is based on the change in conductivity to determine the moisture change brake fluid. It shows clearly the extent of moisture contained by the light-emitting diode, high moisture content will lead to lower boiling point, affectbraking performance. Red indicates the brake fluid needs immediate replacement, green represents good condition, yellow indicates the state is acceptable but soon replaced.1, the green LED lights = water content in the brake fluid H2O3%, can not continue to use the brake fluid needs to be replacedRed LED: change brake fluid4, LED red flashing: battery replacement5, LED yellow: low moisture content, check again in six months6, LED green: brake fluid lines / cell rowFeatures:Five LED indicators show the test results more accurate.Testing DOT 3, DOT4, DOT5 brake fluidPress the switch to turn on the power, the green LED light that represents the battery properly, the green light does not shine on behalf To replace the batteryAutomatic shutdownTechnical parameters:Green: Battery OK, that is, brake fluid does not contain waterGreen / yellow: brake oil in water content of less than 1%, better brake fluid performance, ease of use.Green / yellow / yellow: brake oil in water content of about 2%, brake fluid can continue to use.Green / yellow / yellow / red: brake oil in water content of about 3%, the proposed replacement of brake fluid.Green / yellow / yellow / red / red: brake oil in water content of at least 4%, the brake fluid must be replaced immediately responsible for very dangerous.