Through Transcutaneous Electronic Nerve Stimulator technology, this product is designed with a foot mat as electrodes to stimulate your feet, ankles, achilles tendons as well as temporary relief of pain associated with sore and aching muscles Transcutaneous Electronic Nerve Stimulator is indicated for temporary relief of pain associated with sore and aching muscles in the shoulder, waist, back, neck, upper extremities (arm) and lower extremities (leg) due to strain from exercise or normal household work activities.