There has been many differet ones over the years from wearing one around your neck to keep the bugs away .
I had a close frien who raised chickens big time he put in many around his barns to keep the rats away .
None have ever worked that I know of so to me they are a BIG scam… Roy
They worked for me Roy and I own quie a big barn, also worked for all kinds of pests in my attic.
I know this is kind of old thread, but these devices are still in use and a lot of people are using them, Im quite sure they are improving with every year - just take a look at amazon and bunch of reviews these devices receives from customers - people are saying they worked for them so Im not alone in this subject.
Actually I wrote quite big review about them you can read it here if you are interested
I’ve been a licensed pest control/termite/lawn & ornamental operator since 1978.
These devices are not effective.
They may help out a little at first, but after time I’ve seen roaches crawling right on & in them.
They get used to the sound waves - “behavioral resistance” is the term. Especially for rodents.
I have a friend that owns many radio transmitter sites on mountain tops here in Northern CA and I help with managing them. We use the plugin ultrasonic devices on the sites and have for about 9 years. We found they work best if you can plug them in high so as we have outlets in ceilings and cable racks we plug them in and face downwards. We only have returns when a unit fails which is about every 4-5 years. A nice thing is the frequencies use do not bother dogs.
They are BS.
During an inspection, a spider was crawling across the Ultrasonic Pest Repellers device.
They are a dead giveaway that the home your inspecting has rodents or bugs. Other than that they are worthless.