The LH9135 is a digital brake fluid tester with leds, powered by a type 6F22 9v battery.
Their main features are: inexpensive and easy to use.
Designed to work with any kind or brand of brake fluid tester based in glycol.
Readings are made over a 10 leds scale (light emitting diodes), which allows a high resolution measuring.
The purpose of this tester is to determine whether the amount of water absorbed by the brake fluid is excessive or not. When the brakes are submitted to stress their temperature raises, and this may cause water vapour bubbles forming in the hydraulic circuit causing brake fading.