There are many pathogens that will not be killed with a Clark zapper because you need the exact frequency to eliminate them.
That said, I use a zapper called a Terminator II by Don Croft that is small enough to be wearable on a regular basis. It is particularly good as a protective device when in a contagious zone. Any airline flight is a contagious zone for multiple pathogens.
I have tested the effect of using a standard Clark zapper while treating with an exact frequency for a pathogen with the FSCAN. It seems to increase the efficiency of the FSCAN treatment by about 60%, i.e. if the FSCAN alone is 100%, add the Zapper and you get 160%. Treatment time needed will decrease proportionally.