The impulse created only works where it should on the spot where you are having pain easy and quick use can be used on acute and chronic pain areas it doesnt need a battery or mains supply can be used anywhere just press the button and a short electric impulse is triggered via the piezo crystals in the inside use place the device directly on the area where you are having pain press the upper button 30 40 times this only takes a minutethat stimulates the brain to send endorph