Four-channel (up to 8 electrodes) portable system offers 7 TENS modes, NMS, High-Volt and Interferential stimulation all in one unit. Features LCD screen and digital keypad. Includes a patient lock system that prevents patients from changing set parameters. Compliance meter displays patient usage. Includes A/C adapter, sample electrodes, lead wires and case. Waveforms: Symmetrical Biphasic Square Wave; Asymmetrical Biphasic Square Wave; Sine Wave; and Monophasic High-Volt, Twin Peak.