Features Multi-functional electrical test tool that can be used to test and activate each part of your vehicle's electrical system. Supports various functions such as voltage polarity, relay and diode, fuse, circuit connection status, light and motor check, short circuit location, ground fault detection, cable and connector polarity, 2V-24V DC voltage measurement and more. Features Designed to protect your vehicle's computer while operating safely, compared to traditional power circuit probe sets. Sharp probe tip allows wire to easily penetrate and use in tight spaces. Easy to use: Equipped with a bright LED backlight display, it can read the voltage clearly regardless of day or night. LED light indicator helps you quickly identify the positive and negative polarity of the cable or connector. How to use: When the probe tip comes into contact with the positive pole, the red LED will light up when it comes into contact with the negative pole, so you can easily identify the polarity. Caution: Do not use near steam and dust. When you press the switch, the current will flow from the battery to the tip of the probe and spark may occur when it comes into contact with the ground or circuit. Do not use with household current of 110V/220V. This product is only for DC 6V-24V systems. For detailed operation instructions, please check the user manual in the product package.