Ultrasonic Pest Repellents

I found an ultrasonic pest repeller at a discount store. It emits sound at greater than 20KHz to deter pests like mice and some insects. Here's a similar product with a detailed description.

I was intrigued by the fact that it wasn't the typical poison solution. So, I bought it.

It's also a blinking nightlight, which may attract bugs. Wikipedia says "Some people claim that they work for them, while others claim they are not effective at all. Here's a detailed explanation of ultrasound.

I've tried it and I still notice insects indoors. In fact, this morning, I noticed a green insect that looked like a large mosquito. Photos don't do it justice. It was a lime green.

Maybe the ultrasonic device attracted and stunned it. It was flying around slowly enough so I caught it with my hand.

I'm not convinced that the ultrasonic pest repellent works well against mosquitos and no-see-ums, but I'm going to keep using it and see how it goes.

I had a little concern about whether the low volume ultrasound is safe. It most likely is, and I base that statement on the fact that it's very low volume. I measured it and it's around 50-60 Db right next to the unit. Normally, I'm about 5-10 feet away or more.

Is it annoying? I'm not sure what impact it has on sleep. I bet it's a lot like any ambient noise. You get used to it, but you are more comfortable without it.

Do you know anything about ultrasonic devices like this? All I can say is that I still notice those little no-see-ums at night.