Instruct: Classify a review into positive or negative sentiment.
Query: Does not work at all.

I tried this device on a couple of small dogs that bark incessantly in my neighborhood. I walked up within 3 feet of them, pointed the device directly at them, pressed the button firmly for 20 seconds and it had absolutely no effect whatsoever. As a matter of fact, I think they even increased their barking frequency. Maybe this works for others, but a waste of money for me.