H-wave is similar to the TENs machine and can be used for pain relief, however with horses it is used a lot for decreasing muscle tension and muscle fasciculations. It creates muscle contractions through the pads, this increase in contractions increases the blood circulation and brings new oxygenated blood and nutrients along with stimulating the lymphatic system and improving drainage through the area. It can be argued that this along provides an element of pain relief through removing tension from the muscle which would cause an element of discomfort, and through removing pain producing chemicals and toxins in the area, flushed out through the increase of circulation.