Brake lines are subject to high temperatures; therefore, a certain amount of evaporation and condensation happens within the lines. As this persists the water content in the lines increases beginning to dilute the brake fluid. The Powerbuilt Universal LED Brake Fluid Tester is an easy-to-use pocket-sized tester for water contamination in vehicle brake lines. The tester works on DOT 3, 4, and 5.1. DOT 3 brands, specifically AC Delco, Prestone, Motorcraft, Pennzoil, and Toyota. With 5 LED lights, the tester indicates the level of water in the brake fluid and when to replace it. The included AAA battery powers the tester, and a sturdy plastic cap protects its testing prongs. This LED tester is perfect for the busy shop or the DIY mechanic.