Flex meter (18") accurately measures TRUE RMS AC current, AC voltage, resistance, frequency and inrush current. Flexible Rogowski coil easily maneuvers around cables that are hard to reach or deep within cabinets. Flex meter (18") accurately measures TRUE RMS AC current, AC voltage, resistance, frequency and inrush current. Flexible Rogowski coil easily maneuvers around cables that are hard to reach or deep within cabinets.