Bests & Worsts Reviews from Amazon

Since moving into the house I currently reside, we have had annual problems with bats roosting under our front porch which acts as sort of a bat cave (See the photo I uploaded on the product description page). They are usually gone by sunrise, but they leave little presents behind in the form of bat guano. I've tried other repellants which never work: moth balls, and other ultrasonic systems (supposedly designed to target mice). I've also read online that ultrasonic repellants supposedly do not work on bats which left me skeptical that this product would work. I was so sick of sweeping the un-slightly bat guano every morning (I have a dog who likes to sit on our front porch and survey his surroundings), and am also worried about what diseases (rabies?) these vermin carry, that I finally succumbed to the temptation of the 5 star reviews on this product page to buy one of these. The seller/developer of this product does offer his company's email and phone (and will respond to your email if you email him) and a one year money back guarantee. The seller/developer wants you to try it for 4 to 6 weeks before giving up. Visual inspection of the unit, it appears little more than a small plastic case housing a couple of tweeters and a few setting switches to optimize the ultrasonic profile to disorient bats. I am not sure of the ultrasonic range of the tweeters...how far above audio they go, but they do seem to have an effect on bats. I have not had to sweep bat guano off the front porch since installing the ET pest control (3 weeks now after a losing 4 year battle). Its power line operated, not battery operated, so it may require (as in my case) an extension cord. I've not measured how much power it consumes but I think its on the order of a couple of Watts which is insignificant. So my hat is off to D&R Technologies....a job well done. I'll probably buy another unit for my back porch. Update: Seems amazon deleted my photo of one of the little bats that used to hang out on my front porch. Sorry folks. 2nd update: Looks like the photo is back! Cool.