The HANMATEK AC3 Voltage Tester is a multifunction electrical testing pen designed for fast, safe, and accurate troubleshooting of home and industrial AC circuits. Powered by a single 1.5V AAA battery, the AC3 features a 12×27.5mm LCD display, dual-color safety backlight, and a built-in flashlight for low-light work. Upon powering on, the tester defaults to NCV (Non-Contact Voltage) mode, allowing you to detect AC electric fields without touching live conductors. With three sensitivity levels, the AC3 helps identify live wiring and locate breaks along a line. Pressing the mode button switches to Live Wire Judgment, which distinguishes live from neutral when the probe makes direct contact. The continuity mode (C) lets users determine breaks in wires or check simple circuits through finger contact. The tester can also determine battery polarity (P) when touching positive and negative terminals. In AC Voltage Measurement Mode, users can obtain direct numeric voltage readings from 12–300V, suitable for checking outlets, switches, lighting circuits, or appliance wiring. Data automatically holds after the button is released for convenience. Built with automatic shutdown, reinforced insulation, and CAT I safety level, the AC3 is compact, lightweight, and easy to carry—an essential tool for electricians, DIY homeowners, maintenance workers, and HVAC technicians.