Scope: Wide application, support different DOT3, DOT4, DOT5.1 brake pads. Simple and convenient, one-touch multi-function. Press and hold for 3 seconds to turn on/off, press and hold for 2 seconds to turn on/off the flashlight, press once to select oil type. Excellent performance: the Brake fluid tester uses high-precision sensor with accurate detection results, which can effectively detect the condition of the brake fluid and provide you with a safer driving guarantee. Convenience: LED display 3 colors, 5 level brake fluid status, green light indicates the current brake fluid status is good. When the yellow light is less than 1%, the brake fluid can still work. When the light is red, the brake fluid content is about 3%, it is recommended to replace the brake fluid.