The unit can be hung up, attached to trees, posts and so on or placed freestanding at a maximum recommended height of up to 1.5 metres. If the unit has to be mounted above 1.5 metres, it should be angled down toward the dog's location so that the speaker faces toward the dog, without intervening physical barriers such as fences (open mesh excepted) between it and the dog.
How the Petsafe Outdoor Bark Deterrent - PBC19-11794 Works
This unit can be used to reduce barking from your own dogs outdoors or to help control neighbouring dogs that bark in the vicinty of your fence. It looks like a bird house so if it is used for neighbours' dogs, they will not necessarily be aware that it is helping to control their dogs barking. An internal microphone picks up barking from up to 15 metres away and activates the ultrasonic signal. The unpleasant (but inaudible to humans) sound stops when the dog stops barking. The dog associates the unpleasant noise with its barking and reduces its barking to avoid the sound.