Powerbuilt brake fluid tester. This compact and handy pen tester with LED indicator quickly and accurately determines the water content of DOT3, DOT4 and DOT5.1 brake fluid. Using the tester is effortless: just turn it on, dip the dipstick into the brake fluid reservoir and check the LED indicators. One of the main advantages of this tester is its accuracy. It complies with strict European CE and RoHS standards, which guarantees reliable results. The compact size and built-in pocket clip make the tester very convenient to use. The tester is powered by AAA batteries.