Electrodes, TENS, Misc. - IF-4000 interferential therapy unit, portable/battery, AC adapter, complete : 4 Modes. Continuous, 1/1 abrupt, 8/8 abrupt, 10/10 ramped. Frequency shift: from 25% below set frequency to 55% above. Carry Frequency: 4000 Hz. Modulating frequency: 1-150 Hz. Wave form: symmetrical bi-phasic square. Includes stimulator, lead wires, 4 self stick disposable electrodes, 9V battery, AC adapter, plastic carrying case, and instructions.