{"product_id":"brake-fluid-checker-pen-5-led-dot3-dot4-dot5-moisture-tester","title":"Brake Fluid Checker Pen | 5-LED DOT3\/4\/5 Moisture Tester","description":"\n\u003ch2\u003eBrake Fluid Checker Pen – 5-LED DOT3\/4\/5 Moisture Tester\u003c\/h2\u003e\n\u003cp\u003eKeep your braking system in top condition with this compact \u003cstrong\u003eBrake Fluid Checker Pen\u003c\/strong\u003e. In just seconds, its 5-LED indicator shows you the exact moisture content of your brake fluid — helping you know precisely when it's time for a change. Compatible with DOT3, DOT4, and DOT5 fluids, it's the must-have diagnostic tool for cars, trucks, and motorcycles.\u003c\/p\u003e\n\n\u003cp\u003eMade in Mainland China.\u003c\/p\u003e\n\n\u003ch3\u003eKey Features\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\n\u003cstrong\u003e5-LED Color Display\u003c\/strong\u003e – Instant visual readout of brake fluid moisture level from safe to critical\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eDOT3 \/ DOT4 \/ DOT5 Compatible\u003c\/strong\u003e – Works with all common brake fluid types\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAuto Shut-Off\u003c\/strong\u003e – Automatically powers down after 12 seconds to conserve battery\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eCompact Pen Design\u003c\/strong\u003e – Lightweight and portable; fits in any toolbox, glove box, or garage drawer\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eSimple One-Button Operation\u003c\/strong\u003e – Press, dip, and read — no calibration required\u003c\/li\u003e\n  \u003cli\u003e\n\u003cstrong\u003eAccurate Moisture Detection\u003c\/strong\u003e – Measures water content from below 1% up to 4%+\u003c\/li\u003e\n  \u003cli\u003eRequires 1 × AAA 1.5V battery (not included)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eLED Indicator Guide\u003c\/h3\u003e\n\u003ctable style=\"width:100%; border-collapse:collapse;\"\u003e\n  \u003cthead\u003e\n    \u003ctr style=\"background:#f5f5f5;\"\u003e\n      \u003cth style=\"padding:8px; border:1px solid #ddd; text-align:left;\"\u003eLEDs Lit\u003c\/th\u003e\n      \u003cth style=\"padding:8px; border:1px solid #ddd; text-align:left;\"\u003eMoisture Level\u003c\/th\u003e\n      \u003cth style=\"padding:8px; border:1px solid #ddd; text-align:left;\"\u003eStatus\u003c\/th\u003e\n    \u003c\/tr\u003e\n  \u003c\/thead\u003e\n  \u003ctbody\u003e\n    \u003ctr\u003e\n      \u003ctd style=\"padding:8px; border:1px solid #ddd;\"\u003e🟢\u003c\/td\u003e\n      \u003ctd style=\"padding:8px; border:1px solid #ddd;\"\u003eNo water detected\u003c\/td\u003e\n      \u003ctd style=\"padding:8px; border:1px solid #ddd;\"\u003eBattery OK \/ Fluid Good\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd style=\"padding:8px; border:1px solid #ddd;\"\u003e🟢🟡\u003c\/td\u003e\n      \u003ctd style=\"padding:8px; border:1px solid #ddd;\"\u003eBelow 1%\u003c\/td\u003e\n      \u003ctd style=\"padding:8px; border:1px solid #ddd;\"\u003eFluid is in good condition\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd style=\"padding:8px; border:1px solid #ddd;\"\u003e🟢🟡🟡\u003c\/td\u003e\n      \u003ctd style=\"padding:8px; border:1px solid #ddd;\"\u003e~2%\u003c\/td\u003e\n      \u003ctd style=\"padding:8px; border:1px solid #ddd;\"\u003eMonitor fluid; change soon\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd style=\"padding:8px; border:1px solid #ddd;\"\u003e🟢🟡🟡🔴\u003c\/td\u003e\n      \u003ctd style=\"padding:8px; border:1px solid #ddd;\"\u003e~3%\u003c\/td\u003e\n      \u003ctd style=\"padding:8px; border:1px solid #ddd;\"\u003eReplacement recommended\u003c\/td\u003e\n    \u003c\/tr\u003e\n    \u003ctr\u003e\n      \u003ctd style=\"padding:8px; border:1px solid #ddd;\"\u003e🟢🟡🟡🔴🔴\u003c\/td\u003e\n      \u003ctd style=\"padding:8px; border:1px solid #ddd;\"\u003e4%+\u003c\/td\u003e\n      \u003ctd style=\"padding:8px; border:1px solid #ddd;\"\u003eReplace fluid immediately\u003c\/td\u003e\n    \u003c\/tr\u003e\n  \u003c\/tbody\u003e\n\u003c\/table\u003e\n\u003cp\u003e\u003cem\u003eNote: LED readings are for reference guidance only.\u003c\/em\u003e\u003c\/p\u003e\n\n\u003ch3\u003eHow to Use\u003c\/h3\u003e\n\u003col\u003e\n  \u003cli\u003eRemove the cap from the test pen and open the brake fluid reservoir cap on your vehicle.\u003c\/li\u003e\n  \u003cli\u003eImmerse the test probe into the brake fluid in the reservoir.\u003c\/li\u003e\n  \u003cli\u003ePress and hold the power button for 1 second — the LEDs will display the moisture reading.\u003c\/li\u003e\n  \u003cli\u003eThe pen automatically shuts off after 12 seconds.\u003c\/li\u003e\n  \u003cli\u003eAfter use, rinse the test probe with clean water and replace the cap.\u003c\/li\u003e\n\u003c\/ol\u003e\n\n\u003ch3\u003eImportant Notes\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003eIf the green LED does not illuminate after pressing the power button, replace the AAA battery.\u003c\/li\u003e\n  \u003cli\u003eRinse the test probe with clean water after each use.\u003c\/li\u003e\n  \u003cli\u003eDo not leave brake fluid reservoir open for extended periods — brake fluid absorbs moisture from the air.\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eWhat's in the Box\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e1 × Brake Fluid Checker Pen (AAA battery not included)\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003ch3\u003eRelated Products You May Like\u003c\/h3\u003e\n\u003cul\u003e\n  \u003cli\u003e\u003ca href=\"\/products\/4-pack-deer-whistle-wildlife-alert-devices-vehicle\"\u003e4-Pack Deer Whistle Wildlife Alert Devices for Vehicles\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"\/products\/2-pack-s-hook-brake-caliper-hanger-hooks-rubber-tips-2-pack\"\u003e2-Pack S-Hook Brake Caliper Hangers with Rubber Tips\u003c\/a\u003e\u003c\/li\u003e\n  \u003cli\u003e\u003ca href=\"\/products\/25-in-1-precision-magnetic-screwdriver-set-pro-repair-tool-kit\"\u003e25-in-1 Precision Magnetic Screwdriver Set | Pro Repair Kit\u003c\/a\u003e\u003c\/li\u003e\n\u003c\/ul\u003e\n\n\u003cp\u003eLearn more: \u003ca href=\"https:\/\/www.fueleconomy.gov\/feg\/drive.shtml\" target=\"_blank\" rel=\"noopener\"\u003eFuelEconomy.gov driving efficiency guidance\u003c\/a\u003e\u003c\/p\u003e\n\u003ch3\u003eFrequently Asked Questions\u003c\/h3\u003e\n\u003ch4\u003eQ: What brake fluid types does this brake fluid checker pen support?\u003c\/h4\u003e\n\u003cp\u003eA: This brake fluid tester is compatible with DOT3, DOT4, and DOT5 brake fluids, making it suitable for most cars, trucks, and motorcycles.\u003c\/p\u003e\n\n\u003ch4\u003eQ: Do I need to calibrate the brake fluid checker pen before use?\u003c\/h4\u003e\n\u003cp\u003eA: No calibration is required. Simply insert a AAA battery, dip the probe into your brake fluid reservoir, and press the power button for a one-second reading. The 5-LED display instantly shows the moisture level.\u003c\/p\u003e\n\n\u003ch4\u003eQ: How do I know when to replace my brake fluid based on the LED reading?\u003c\/h4\u003e\n\u003cp\u003eA: When 4 LEDs light up (green, yellow, yellow, red), moisture is approaching 3% and replacement is recommended. When all 5 LEDs illuminate, moisture exceeds 4% and the brake fluid should be replaced immediately for safe vehicle operation.\u003c\/p\u003e\n\n\u003ch4\u003eQ: What battery does the brake fluid tester use?\u003c\/h4\u003e\n\u003cp\u003eA: It requires one AAA 1.5V battery, which is not included. Open the battery cover by following the arrow direction indicated on the pen body.\u003c\/p\u003e\n\n\u003cscript type=\"application\/ld+json\"\u003e{\"@context\": \"https:\/\/schema.org\", \"@type\": \"FAQPage\", \"mainEntity\": [{\"@type\": \"Question\", \"name\": \"What brake fluid types does this brake fluid checker pen support?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"This brake fluid tester is compatible with DOT3, DOT4, and DOT5 brake fluids, making it suitable for most cars, trucks, and motorcycles.\"}}, {\"@type\": \"Question\", \"name\": \"Do I need to calibrate the brake fluid checker pen before use?\", \"acceptedAnswer\": {\"@type\": \"Answer\", \"text\": \"No calibration is required. Simply insert a AAA battery, dip the probe into your brake fluid reservoir, and press the power button for a one-second reading. 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