Brake Fluid Liquid Oil Tester Pen 5 LED Indicator Car Testing Tool For DOT3/4/5

Green/yellow/yellow: The brake fluid has a water content of about 2% and the brake fluid can continue to be used. High water content will cause the boiling point to decrease, affecting the braking performance, and corrosion of the brake master cylinder and the sub-pump, causing rust and seizure.

eBay