The OmniSite Amp Probe will monitor AC motor amperage from 0-50, 0-100, or 0-200 amperes. The sensor outputs a 2-wire, 4-20mA signal. The sensors are a solid-core, where the conductor runs through the sensor. Amp probes are not needed to calculate pump on/off cycles and runtime, but are recommended to display pump amperage. Works only with the Crystal Ball product. Please call into our sales department, 317-885-6330 ext.4, with any questions.