Bests & Worsts Reviews from Amazon

Yes, somebody with a degree in engineering and whose job it is to think very logically. First, within the ad there is the mention that these repellents are ultrasonic. That means the sound is above the human hearing range. It's a metallic electro-mechanical buzzer with moving parts and significant mass, for Pete's sake. It is NOT ultrasonic. So ... I tested four units from my last purchase, and three from a prior purchase, and I had five weeks of continuous testing using all of those (and more weeks accounting for the earlier purchase). And to be perfectly clear, my yard has moles and gophers, but no voles. And, since I had so many units, I could place them MUCH closer than recommended. Seeing that I couldn't realistically claim any success at first, I decided that there is a small chance that these critters will not move far (or perhaps not move at all) while they are taking care of their pups (which will leave the nest 33-days after being born). That said, not all the those rodents in my yard will have pups at the same time. In addition, during the entire test period, I continued to try and flood them out with hose and water under pressure every day. That probably wouldn't drown any adults, but it would probably eliminate a few pups as they drop off their mother as she scampers to get away from the water. And -- last but not least -- I didn't place any repellent near an active hole (indicated by a mound of dirt, which I would flush back into the hole using hose and water on a daily basis). That said, those critters managed to make new mounds of dirt right next to some of the repellents (where there were no mounds originally). So what is the best (spelled ONLY) way to get rid of those critters? Answer: traps. I have extensive experience with those. The best trap (and which you can buy at Amazon) is the Victor black box trap. Always buy them in pairs so you can place them back-to-back in an active tunnel. What's a non-active tunnel? Answer: one which is blocked in one direction because it is only used to push dirt out of an active tunnel. You can test for that by pushing in a short section of old hose to see if the tunnel continues in both directions. So dig a hole big enough for two traps placed back-to-back then cover the hole with a small board so no light gets in, and put something heavy over the board. By the next morning the deed will have been done. That process is virtually 100% effective every day until there are so few rodents left that you have trouble finding exactly where they are. In fact, last year I set four pairs of traps one day and had four dead rodents the next morning; then reset the traps that day and had four more dead rodents the following morning. What are my results with the solar repellents? Probably have twice as many rodents as I had a month ago. I'm giving this product one star because even a total failure has the value of being educational.