Auto Car Brake Liquid Tester Sound Light Alarm Car Diagnostic Check Pen HD Backlight Screen Waterproof for DOT3/DOT4/DOT5.1. 1 x Brake Fluid Tester Pen. Function Switch Key: After starting, press S key to switch to DOT3/DOT4/DOT5.1, and press S button to switch the brake oil type (default is DOT3).
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