Expert Quality, easy to use brake fluid tester. Just select the brand of the brake fluid to be tested. Then simply immerse the tester probe in the brake fluid for 1 second. The LEDs fitted to the tester then display a relevant coloured LED, indicating the water content. Equipped with an LED light at the probes, helping to illuminate dark brake reservoirs. Compatible with Dot 3, Dot 4, Dot 5.1, AC Delco Dot 3, Pennzoil Dot 3, Prestone Dot 3, Motorcraft Dot 3 and Toyota Dot 3. Fitted with 1 AAA battery (supplied).