Interferential therapy unit , ift , we make use of two medium frequency alternating these medium frequency currents are not identical & may differ in frequency up to 150 Hz. Two oscillator of frequency are generated & are cross widely applied to the body by means of four electrode pads. (CH1 & CH2) channel with one pair of pads i.e 2Nos of pads. One oscillator has a fixed frequency of 4000 Hz the other ranges in the frequency between 3850 Hz both oscillator interfere i.e intersect inside the body resulting in a signal as a carrier & low frequency part ( the difference in frequency ) for the actual therapy. In simple words define the interferential therapy as when two medium frequency currents i.e CH1 & CH2 intersect with easy leading interference current to be generated at the place. For example , let us take two medium frequency current in CH1 =4000Hz & CH2 = 3850Hz.you can purchase quality ift unit from SPT seetaphysiotech for pain relief.