Smart Relief offers powerful, portable relief of knee and shoulder pain by bringing TENS technology to pain sufferers in a convenient, affordable way. FDA approved for relief of chronic pain associated with arthritis. Blocks the body's pain signals by sending gentle electrical pulses along the nerve, which reach the brain before the pain signals do. The electrical pulses of Smart Relief are generated by a small, battery-powered device and provides the same type of TENS relief you find in physical therapy facilities. Smart Relief offers 63 customizable intensity levels; is safe, FDA approved, easy to use with no wires, no assembly and no prescription needed.