If youve heard of TENS (transcutaneous electrical nerve stimulation) then youll know its a form of therapy that uses a mild electrical current to gently stimulate muscles and provide effective pain relief. Paingone One works on the same principle, but simplifies it down to the click of a button no wires, batteries or gels. It even works through clothing! Carry anywhere, for fast, temporary, drug-free pain relief on-the-go. L13.3cm. Not for use when pregnant, if you are epileptic or if you have a pacemaker.