Features: Correctly connect the battery clamp of the instrument to the batteryterminal. The red clamp isconnected to the positivepole and theblack clamp isconnected to the negativepole. After the correct connection, the LED display will display the realtimevoltage of the measured battery, and the LED light will turn on to indicate the batterystatus. When testing thegenerator charging system, please keep the tester correctlyconnected to the batteryterminal, and then start thegenerator. At this time, the output voltage will be displayed on the LED display screen, and the LED indicator on the right side will light up to indicate thestatus of thegenerator. LED related instructions: Fullled lights are on inFULL gear, and the battery is in normalstate. MEDIUM- The LED lights on inMEDIUM gear, and the battery voltage is slightly low, which need to becharged. The low-LED light on intheLOW gear, the battery is insufficient and need to becharged, and the buzzer alerts. EMPTY- When the LED light on, the battery is completely out of power and need to becharged. DEAD- The LED light on intheDEAD gear, the battery voltage is too low, and the buzzer indicates that there should be aproblem with the battery. At this time, the battery should be checked by a engineer to see whether it should be replaced. Reverse-led lights on inREVERSE gear, battery tester isconnected to batteryterminal post in REVERSE, and buzzer gives alarm. GOOD- The LED light on inGOOD gear, and the output voltage of the alternator isnormal. High-led lights are on inHIGHgear, and the output voltage of the alternator is HIGH. Specifications: Material: Plastic, Metal Size: Approx. 12.8x5.3cm/5.04x2.09in Cable Length: Approx. 43cm/16.93in Package Includes: 1x Battery Tester note: Please allow 1-2cm errors due to manual measurement, make sure that you do not mind before you order. Due to the difference between different monitors, the picture may not reflect the actual color of the item.