thanks for the info Mrs.L but what i realy wanted input from you or others on real experience regarding flu,coz many days ago i had a running noze for 4 days and my use of the zapper in the standard way did not help at all ,it could be allergy but the thing that bothered me is that many people arround me got the same sypmptoms and they were telling me its a flu! thats why i want this experience to determine may be the specific freq for flu say for one hour could do the job,rather than the standard program.