The Dwyer CM-1 digital clamp meter is a low cost, compact instrument ideal for general electrical testing and troubleshooting. A few applications include HVAC, automotive, electrical/power, and environmental monitoring uses. The digital clamp meter measures DC and AC voltage to 600 V, AC current to 400 A, and resistance to 400 Ohms. In addition to volts, amps and ohms, this meter includes a frequency test to 400 Hz. The CM-1 also features data/range hold and auto range buttons to keep the screen from updating when gathering values. The 3-3/4 digit LCD features automatic polarity, overload and low battery indication.