I had read that with these kinds of devices you have more success with males dogs which I have a male dog so thought i'd give it a go. The first two days he sniffed it real good but it did NOT trigger a urine response from him. Now, days later he pays it absolutely no attention. So it's a nice idea but I think these things are very dog gender, breed and personality dependent as to if they'll work for you or not. At least they're not very expensive so if it doesn't work you're not out a whole lot of money.
Didn't work for my pup