Facts on ultrasonic/resonance sound  and electromagnetic pulse

Ultrasound 
Ultrasound are tones whose frequency is above the tonregister people usually can perceive (about 20 - 20000 Hz).

Ultrasound Models Topo Stop E250 and E500 delivers primarily microprocessor controlled random ultrasound in the range of 25000 to 30000 Hz. 
Ultrasound is spread only in the open space in which the mice repeller is located and the sound waves bounce on all hard surfaces like light reflected in a mirror. Ultrasound can not penetrate walls, floors or ceiling! From this we learn that a device mounted for instance in the crawling space underneath the house does not give a satisfactory sound penetration as the animation clearly shows.

Best appliance placement 
In order to ensure good dissemination of the ultrasound in the crawling space that has partition(s) you should try to place, the pest repeller in accordance with adjacent animation. If the partition is thick and opening-up small, it may be good to place a bent sheet of a metal plate (at right angles!) directly in front of the device. The sound from the pest repeller will then be "cut in half" without any energy loss into the two partitioned spaces.

When mounting the device in the attic with partition it is particularly important to affix a bent metal sheet, enabling as much as possible of the first sound beam to reach the end walls of the attic. If not a reflection device is affixed in front of the loudspeaker, the primary sound wave will first hit the angled roof and reflected down into the isolation, which significantly reduces its sounding dissemination.

Ultrasound is not dangerous to people or animals 
Some people have concerns about the ultrasonic could be harmful to humans or animals, but that is not the case for the following two reasons. 
1) In the first place the equipment is almost exclusively mounted in spaces in which we ourselves do not reside (unisultaed attic, crawling space unde the house, etc.) and then, referring to the text above the ultrasound remains in this space.
2) Secondly, we are surrounded by a conglomeration of various ultrasound from fluorescent lighting, TV sets, refrigerators and other electrical installations. The only negative report ever heard of is that fluorescent lamps with somewhat too low frequency (approximately 60000 Hz) could induce headaches with some individuals.

Resonance sound 
Resonance sound are tones of low frequencies (approximately 30-500 Hz). This sound is on the one hand audible, on the other hand it creates a micro vibration throughout the frame work of the house.
Concern has in different contexts been expressed that low frequencies could cause harm to humans. It is important to know that this only applies to purely subsonic sound waves (below what humans can hear), that is to say frequencies lower than 30 Hz.
Topo Stop R100 is a resonance sound device with a frequency range of 80-100 Hz. Dually with ultrasonic sound (Topo Stop E250) a comprehensive disruptive sound wave will be created in the house. In more difficult circumstances with complex rodent habitats, it is sometimes necessary to install both resonance and ultrasound devices (statistically in 1 case of 8).

Electromagnetic pulse 
Electromagnetic pulse or more correctly electromagnetic fields are formed around all electrical wiring. Topo Stop like all other electrical appliances creates when in operation a small change in the electromagnetic field in the wiring system to which the device is connected to. However, the change is barely measurable and therefore completely neglectable.

Some producers of electronic pest repellers argues that the electromagnetic pulse their equipment generates scares off all mice from walls, floors and ceilings on the basis that the electromagnetic field spread in the framwork of the house via the electrical wiring. Experts all over the world claim this is only a sales gimmic and no producer has ever presented any scientific proof of the effectiveness of electromagnetic pulse.