I had four of these plugged in my garage years ago.

Didn't deter the mice in the garage, but maybe the newer ones work.

What seemed to work for me was Shaved Irish Spring (regular) wrapped up in dryer sheets with an elastic band. I tossed them everywhere

in the garage and put these small bundles everywhere in the car. It seemed to work. I didn't see any signs in my car of mice and the smell doesn't last.

Of course I need to replenish the bundles when the smell disappears.

Somewhere on the site we had a discussion about cars and mice.

-G

Found this ...

https://www.mcgill.ca/oss/article/technology-you-asked/are-ultrasonic-pest-repellers-effective#:~:text=Thus%20when%20some%20studies%20show,is%20simply%20not%20enough%20evidence.

Thus when some studies show that pest infestations do decrease,

they have no way of proving that it was a result of the ultrasonic sound.

For these reasons, researchers strongly advise against buying into these devices.

There is simply not enough evidence.Nov 27, 2017