Fine tune the ultrasonic frequency range: 20hz-65khz (inaudible to human ears) It can cover 80 to 120 square meters Put one in a room, because ultrasound cannot penetrate walls and solid objects Use low frequency ultrasound
Fine tune the ultrasonic frequency range: 20hz-65khz (inaudible to human ears) It can cover 80 to 120 square meters Put one in a room, because ultrasound cannot penetrate walls and solid objects Use low frequency ultrasound
