"Micro Plus Microcurrent Electrical Nerve Stimulator two channel analog device with 3 polarity settings. Positive, Negative, or BiPolar. The device has adjustable Pulse Rate 0.5-120Hz, Pulse Duration 1-3s, and Micro / Milliamp Control. The unit is powered by one 9-Volt battery. Unlike traditional TENS units, MicroCurrent (MENS) output is at a lower level, and therefore the stimulation is often not ""felt"" or perceived by the patient. Device comes with lead wires, electrodes (4), battery, instruction booklet and carrying case."