considered one for my boys. ruled it out for various reasons, but mainly because I felt it would be less effective with the two of 'em. there was a fair amount of skepticism as well, I just couldn't see a little zap stopping them if they were chasing down some small, furry thing. I just trusted a physical fence more, although at my next place I definately want to put in a taller fence, to eliminate the possibility of them jumping it. my current fence, I'm sure they could jump if they wanted to.