THE WV GROUP INDUCTION MACHINES are based on band width of 0KHz-1400 MHz. The high frequency is  from 30-80 kz, the super high is from 50-1.4MHz  and Medium is  from 1khz to 20 Khz.  So whenever we are referring to medium frequencies we are talking of band1-30KHz, frequencies, In heating of materials many methods were used earlier and are still prevalent, namely Oil, wood, coal ,gas ,electricity etc.  Our method is different than any one of them , we use Induction, which means we directly transfer the energy into the component under heating and that makes it the fastest method of heating  . In all other methods the Job is not directly transferred the energy , a surrounding atmosphere is created around the Job which absorbers the surrounding temperature (heat) and  absorb the energy in form of Kilocalories ,  In short there are huge losses in heating the media surrounding the job, also the losses due to radiation losses and in effect huge loss of Kilocalories of energy , Which make induction heating superior to any of these methods since it is heating not the media surrounding the material but is heating the material itself.