I purchased a new tens unit in the spring that was suggested to me by the young man that was giving me PT. It was referred to as a activity unit I think. It has 4 gel pad electrodes that attach to the belt as does unit that operates the electrodes. This unit releases from the belt and clips into the charger as one unit. There are no wires to deal with. The belt, with the gel electrodes are worn under you clothing, no wires needed, no unit clipped to your belt or in you pocket. I don't think Medicare will pay for it but maybe private insurance will. I paid for my own and get my own gel patches on line. this unit is made by Empi. It's very nice because it very portable and comfortable. I've have several brands of tens units and othe then the name on the units and the amount paid for each, I've found all to be very useful. I use it on my back , my shoulder and my knee. I'm sure that there will be more uses down the road.