It is easy to detect the fire/zero line and know which line has a bad situation. Features: With self checking function to know whether the pen battery works on or not. LED indicate light, long service time and convenient to view the detection result. The nib is designed with a screwdriver, which is convenient for you to open the socket box at any time. Pen clip design, mini size and light weight for easy carrying. A perfect tool kit for home and electric industry uses. Specifications: Quantity: 1pcs Color: transparent Material: PC+metal Measuring range: 70-250V Item length: 155mm / 6.1in Screwdriver size: 17 * 4mm / 0.7 * 0.2in Battery: 3 * LR41, 1.5V, 25mAh Package size: 185 * 70 * 30mm / 7.3 * 2.8 * 1.2in Package weight: 30g / 1.1ounce Packing List: 1 * Voltage Tester Pen