Radarcan DOG BARKING SILENCER PRO User Manual page 9

Ultrasound consists of high-frequency sound waves which
are perceived by dogs, but are inaudible to humans.
The ultrasound waves fan out uni-directionally from the
DOG BARKING SILENCER PRO, like fluorescent light. Hard
substances (walls, ceilings, furniture, glass, etc.) promote
better spreading out of the sound waves, as they bounce
off these surfaces, whereas soft materials (cardboard,
curtains,carpeting, etc.) absorb the sound waves.
Human
Bat
Mosquito
Butterfly
Fly
Cockroach
Cricket
Dog
Grasshopper
Rodent
Dolphin
Mole
Others
Audible Ultrasound
Table of
frequencies
within the human
hearing range
between
20 Hz y 20 Khz,
compared with
the approximate
hearing range
of different
animals and
insects.