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. What's in the package: 1 x TENS Machine, 4 Palm Electrode Pads, 2 Large Rectangle Pads, 2 Small Pads, 2 x 1/2 Lead Wires, 1 x 1/4 Lead Wires, 1 x USB cable, 1 x User Manual, 1 x Pad Holder, 1 x Pouch.