HT663L Brake Fluid Tester Quickly assess brake fluid moisture content to help determine if replacement is needed. The handheld tester provides instant readings with a threecolor backlight and audible alerts for clear, actionable results. Key benefits Fast, clear results: Instant moisture measurement on a large LCD so you can decide quickly if fluid service is required. Simple operation: Plug the 132 mm flexible metal probe into the reservoir and read the value and colorcoded alert. No complicated setup. Reduced uncertainty: Threecolor backlight and buzzer patterns translate percentage readings into easy recommendations for replacement timing. Portable and durable: Compact plastic housing fits in the hand and stores easily in a toolbox or glove compartment. How it works Insert the probe into the brake fluid reservoir and switch the unit on. The LCD displays moisture percentage and the backlight indicates condition: Green backlight for 0 to 2 percent: fluid condition acceptable. Yellow backlight with slow buzzer for 2 to 3 percent: replacement recommended. Red backlight with fast buzzer above 3 percent: immediate replacement advised. sensitivity probe plus audible alarm delivers instant, easytoread feedback in all lighting conditions. Features Model: HT663L Compatibility: Works with DOT3, DOT4, DOT5.1 and most synthetic brake fluids Moisture detection range: 0 to 4 percent Resolution: 0.10 percent; accuracy: ±0.1 percent Probe: 132 mm flexible metal hose for convenient access to reservoirs Display: Large LCD with threecolor backlight for day and night use Alerts: Twospeed buzzer tied to yellow and red alert levels Construction: Plastic housing, compact and lightweight Physical specifications Size: 370 x 24 x 30 mm Weight: 58 g Color: as shown Typical use scenarios Routine maintenance: Verify brake fluid condition during scheduled service to inform replacement intervals. Pretrip check: Quickly test fluid moisture before a long drive to reduce the risk of degraded braking performance. Workshop diagnostics: Portable tool for private workshops, shops, and dealerships to confirm fluid condition when inspecting or servicing vehicles. What it solves Eliminates guesswork by converting moisture content into clear visual and audible signals Helps prioritize brake fluid replacement to maintain system reliability Provides a compact, easytouse test method suitable for use and professional settings Included functions Instant moisture readout with trichromatic backlight Audible alarm with distinct patterns for recommended and immediate replacement Flexible probe for access to various reservoir shapes Model HT663L offers a practical, portable solution for monitoring brake fluid moisture and making informed maintenance decisions.