This new, state-of-the-art TENS unit will get the job done - for up to TWO HOURS per session. Relieve pain, stimulate your nerves and muscles and relax your body - anytime you feel the need. This unit has digital controls for Left and right channels and 20 levels of intensity - from mild to EXTREMELY powerful. Small and Lightweight - At only 4.5 Ozs and the size of a remote control, this unit packs enough power to thoroughly relieve your pain and will travel with you anywhere you like. Take it to the gym, on a trip, or even to the office - it fits in your briefcase or purse - and NEVER needs batteries, thanks to the built-in rechargeable Lithium Ion Cells! This Unit is for Over The Counter Use.