I have been using this device with the Cefaly II for three months and have seen a reduction in the number of severe headaches from 4 days each week to only 1 day each fortnight. I have only experienced one migraine during the three months, down from two per month. The Cefaly II alone made no difference. I would recommend migraineurs to try both devices if they experience little improvement with Cefaly II alone, despite the advice from the manufacturers.