Extech MA445 Information The Extech MA445 is a True RMS AC/DC clamp meter that measures AC current, resistance, capacitance, frequency, duty cycle, and temperature. It also features a non-contact voltage detector (NCV), built-in flashlight, Data Hold, DC Zero, and Auto Power Off. The MA445 is a versatile tool that is ideal for electricians, technicians, and hobbyists. Introduction The Extech MA445 is a compact and powerful clamp meter that offers a wide range of measurement capabilities. It is a True RMS meter, which means that it can accurately measure non-sinusoidal waveforms. This makes it ideal for measuring the current drawn by electronic devices, such as power supplies and motors.