This machine is quite extraordinary I must say. As the weather in the U.K has been extremely hot recent, I have to leave garden doors and windows open as long as possible to cool down the house temperate all day and all night. Annoying flies, daddy long legs and moths are always flying in, un-welcomed of course. There is no way to stop them (unless you want no air in your house whatsoever) However , when I plugged these Ultrasonic Repellers in, I found that there were less flies in my house and all types of insects were reduced and it has stayed this way ever since.
Firstly I've never had a problem with rodents so the effectiveness of these against them I cannot comment on. However, I bought these because of spiders. My daughter is terrified of them so we put one in her room, the other in the kitchen which leads to the main point of entry, the utility room. My daughter has not had a single spider in her room since and as far as the kitchen goes it's much better. Over the years at this time of year when spiders come indoors for mating we have had loads and in the weeks before purchasing these usually at least one or two a day but this has changed. Don't get me wrong and think this is a miracle cure because it's not but it's a massive improvement. Since having these we've probably only had one or two a week and as far as flies and wood louse go, none at all.