In such devices, I am generally skeptical, that I do not trust the promises first times, which makes a manufacturer. We have already set out to return the device after a few days.
The device is screwed in about 50cm height to a bar that we beat into the ground next to the sandpit. In the device now stuck 2 9V blocks. The unit is in a practical protective cap, meaning you can pull it out before the winter and stored in the house for example. It has a neat off switch that is easily accessible at the bottom of the unit. When the device is turned on and something moves in the field of view of the sensor, so I appreciate the range of about 10 meters, it will send out loud and high Fieptöne that are anscheinen uncomfortable for cats. The one hears as a sensitive human being even a little bit - but at night when the cats come anyway I'm next door at the house in bed and hear not.
In the sandbox we have since seen only once 'escape traces "of a cat. For a complete success.
I did not think that works. Since then, the cats make their filth while a few meters away on the meadow - but since we are probably still stand a second device.
Addendum:
After one year of operation now I have to say, unfortunately, that the cats seem to have become accustomed to the sound of the part. That's why I reduce my rating from 5 to 2 stars. Too bad - now I have to look back to what the new. Let's see if I an automatic water sprinkler or something hollow ....
