RADARCAN R-200 Manual De Usuario página 8

Ultrasound consists of high-frequency sound waves which are
perceived by the mosquitos, flies, mice and cockroaches, but
cannot be heard by humans.
Human
Mosquitos
Flies
Cockroaches
Rodents
The ultrasound waves fan out uni-directionally from the PEST
COMPLETE REPELLER HOME 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.
When installing the PEST COMPLETE REPELLER HOME, take
into account that the ultrasound waves do not penetrate walls
(brick, plaster, etc.), or wooden room dividers, glass, plasterboard
false ceilings or other solid materials. Hang the PEST COMPLETE
REPELLER HOME inside the area you wish to protect. Avoid
Audible Ultrasound