Features: 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, affect braking 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 H2O 3%, can not continue to use the brake fluid needs to be replaced Red LED: change brake fluid 4, LED red flashing: battery replacement 5, LED yellow: low moisture content, check again in six months 6, LED green: brake fluid lines / cell row Specification: 1, check the car brake oil quality 2,5 LED lights display the percentage of moisture content in brake fluid 3, auto power off 4, 1 x AAA batteries (not included) Specifications: This design meets the characteristics of our hand grip, improved the practicality and safety, making it convenient and comfortable to use. 30 Seconds tied a hook, no longer ask for help, no longer hurt your hand, no longer time-consuming. Material: ABS, stainless steel, the motor. ABS engineering material is very durable, do not easy to aging. Partial parts are made of stainless steel, anti rust. Size: approx 9CMX7CMX1.5CM. Run by 2 x AAA batteries(not included). Package Included: 1PCS brake fluid tester not retail package