OptiMate O126 Cig Lighter Plug Battery monitor

The plug fits into any diameter 21-22 mm / 7/8 inch 12 V standard cigarette lighter/car socket that is powered when the ignition is switched off, with integrated 10A fuse to protect the electronics. Encapsulated monitor with 4 LEDs shows the battery charge status from full to empty for 12V lead batteries (AGM, GEL or STD) - The LED corresponding to the charging status flashes every 3 seconds. SAE quick connection for charging the battery when needed - With weather-resistant cap for use while driving Indicates charging system status when engine is running - easy check before driving at a glance to see if the battery is charging.