Is the sound audible to humans? ie, is it going to bother my neighbors?
This will only bug your neighbors if they’re the four-legged type.
Many years ago, when I was a kid, my grandparents had something similar in their yard. I could hear it faintly and it was kind of annoying. However, no one else could. About 2 years later I noticed, I could no longer hear it. People are all different regarding how well they can pick up high pitched noise and it degrades with age. I am still more sensitive than most people my age to high pitch noises and the buzz/hum that office halogen lights make, but have never heard one of these things since and the older I get, the less I hear (high pitch noises… and everything in general sadly)
Overall, there is a small chance a young child may be able to hear it, but 99.9% of older kids and adults will have no idea its even on.
This review (and the 307 other critical reviews) may be worth considering before you buy:
good to keep squirrels away and not annoy cats?
My dog loves it so much she won’t go outside anymore and only craps in the house now. LOL!
I kid, but seriously, just like someone else posted above, read reviews before you pay for this stuff.