Feature: 1. Pen Style Brake Fluid Tester: The brake fluid tester pen can detect the condition of DOT‑4 brake fluids and most synthetic brake fluids with fast and efficient testing process. 2. Immediate Test Result Display: The tester adopts diodes to immediately display results in colors, green for <1.5% water, yellow for 1.5‑3%, and red for >3%, indicating the need for fluid replacement. 3. Portable and Compact Design: Well structured case fits comfortably in hand, making it convenient to carry while traveling without taking up much space. 4. Wide Applicable: The brake fluid test strips can check the condition of DOT‑4 brake fluids as well as most synthetic brake fluids, widely applicable for private workshops, repair shops and car dealerships. 5. Universal Compatibility: The automotive brake fluid tester is suitable for most vehicles and could test DOT4 brake fluid accurately and efficiently. Specification: Item Type: Brake Fluid Tester Pen Material: ABS Immediate Results Shown By Diode: Green: < 1.5% water, Yellow: 1.5 - 3% water, Red: > 3% water Function: Automatic shut off Battery: 1.5V AAA battery (not included) Fitment: Universal for most vehicles with DOT4 brake fluid. Package List: 1 x Brake Fluid Tester Pen