Specification Shipping Limitations:Unlimited Available Ship to:United StatesDetails Important Notice: TENS units should NOT be used by individuals with pacemakers, pregnant women, or those with epilepsy. Consult your doctor before use if you have any medical conditions. Block the transmission of pain nerve signals TENS is a non-pharmacological, non-invasive method of pain relief, which stimulates the perceptual nerves by means of a mild microcurrent(usually less than 25 microcoulombs per unit of time) to block the transmission of nociceptive nerve signals to achieve pain relief. Stimulates stationary muscles to prevent atrophy EMS is Electrical Muscle Stimulation, is used as a passive exercise technique to stimulate muscles, assist in muscle strengthening, prevent disuse muscle atrophy, increase local blood circulation, muscle relaxation and toning, and achieve the purpose of muscle recovery and conditioning.