Question about Windhager Animal repellent devices

As a supplement to David-cslu's answer, here is the excerpt from the operating instructions on the adjustable frequencies:

1. (6 - 10 kHz) Strong sound waves audible, do not use near humans (application area pigeons, dogs, game).
2. (13.5 - 19.5 kHz) Sound waves audible to humans (application area dogs, cats, martens, game)
3. (23.5 - 28 kHz) Ultrasonic waves not audible to humans, (application area dogs, cats, rodents)
4. flashing LEDs
5. alternating level 1 to 3 together with level 4

Different frequencies can be set. However, in my experience, even on the maximum setting (all frequencies combined), the animals were not very impressed by the thing. The badger digs a hole right in front of it.