The OEM Automotive Tools Brake Fluid Tester, No. 25267, comes as a reusable, pen-sized device that uses multi-colored LEDs to alert technicians that the brake fluid on a vehicle needs to be changed. Over time, moisture gets absorbed into the fluid and can cause corrosion inside the brake system. This can pose a safety hazard and can also damage ABS components, resulting in expensive repairs. This electronic brake fluid tester makes testing this vital fluid easy and with a testing of only one second, according to the company.