We had mice often. My wife bought a box of these and installed them all over the house and garage. She didn't tell me. I had a headache. The dog was restless. I woke up and went around the house discovering and pulling these out of the outlets so I could sleep. I found each one by the sound.

My wife got mad at me for disconnecting them and said I just pulled them to make her mad.
She said she couldn't hear them and that I couldn't possibly hear them either.

So how did I find them all? (dear).

I left the one's in the garage as I think they work. I see no mouse droppings since they were installed.