Amprobe AD40B Mini-Clamp Ammeter Digital clamp meter measures alternating current (AC) to 400 amp Average-sensing meter provides accurate readings when measuring linear loads, where the current or voltage has a sinusoidal waveform Transformer clamp with 1" (25 mm) jaw opening measures current without touching or interrupting the circuit Hold function keeps the reading on the display, even after the meter is disconnected Meets International Electrotechnical Commission (IEC) safety standard 61010 and is certified for category III installations up to 600V