Cpt leadwire for touch tens post 2012 model can be used with one or two leadwires and two or four electrodes respectively this is the only leadwire which is compatible with the touch tens units with a serialnumber later than svt120020001 these touch tens leadwires are replacement accessories for the tenscare touch tens unit only with a serialnumber later than svt120020001 the leadwires connect the electrodes to the touch tens unit itself they are only suitable for use with the touch ten