The Monnit ALTA Wireless AC Current Meter Sensor is a 20 Amp, battery - powered device that measures the RMS current of alternating current (AC) systems. Utilizing a current transformer (CT) that wraps around the hot wire of a two - wire power system, this sensor provides accurate readings of minimum, maximum, and average RMS current, as well as amp hours. The data collected can be transmitted to the iMonnit system, which can generate watt hour or kilowatt hour readings, making it an essential tool for energy monitoring and management. With a height of 1.1 inches and a width of 2.5 inches, this sensor is designed for easy installation and use in various applications.