Any frequency from 5khz up to 100 kHz bothers most mosquitos species enough that they will not bite. This is a depopulation tool that kills millions of Africans a year that get Malaria from Mosquitos, You cannot speak the word frequency when in Africa. Now here’s a little trick. The House fly and horse fly are as bad in many areas as the mosquito but they won’t tell you what to do about them. Ready. There is some diminished attack at 60 kHz but there is devastation at low frequency. Use the Mole frequency against Flys. Works amazing.