product features: Induction range: 90V-1000V AC Instructions: 1. When the tip of the pen senses or detects a voltage, the white part of the tip of the pen will emit light and beep. It is easy to detect the live wire and know which wire has dangerous voltage. 2. There is a button in the middle of the induction pen. When you press it, there is a high-brightness LED at the tip of the pen. Instrument maintenance: 1. This instrument is safe and insulated. To ensure safety, please keep it dry and clean during storage and use. 2. If the LED light does not turn on, please replace the battery. When it is not used for a long time, you need to remove the battery to prevent leakage and damage to the instrument. Packing list: 1* electroscope (packaging without battery) We only sell test pens, not other items in the picture. Due to differences in different monitors, the pictures may not reflect the actual color of the item. Due to manual measurement, please allow slight size errors.