1/2/4 channel ”TENS” (machine to relieve pain. Now no need to take pain killer nsaid to relieve pain caused by sports injury. Now you can treat yourself at home with a little help and guidance from us. This machine runs on electricity and gives amazingly fast results. Plus 1 year & 3 Years replacement Warranty .. Trans cutaneous Electrical Nerve Stimulation (TENS) Introduction TENS is a method of electrical stimulation which primarily aims to provide a degree of symptomatic pain relief by exciting sensory nerves and thereby stimulating either the pain gate mechanism and/or the opioid system. Mechanism of Action The type of stimulation delivered by the TENS unit aims to excite (stimulate) the sensory nerves, and by so doing, activate specific natural pain relief mechanisms. TENS as a treatment technique is non invasive and has few side effects when compared with drug therapy. Ideal for back pain treatment.