I purchased 2 Riddex Plus units just under a year ago. I was so happy that since I installed one I didn't see any more mice. Low and behold, I was watching TV tonight when I saw a mouse run along the wall right past the unit. So, my guess is that it doesn't really work. Or maybe it only works for a short period of time before the pests get used to the "whatever" it does or is supposed to do. So I'm back to setting up traps for the pesky little creatures. I'll keep the Riddex units plugged in and "think" them into working. read full review »