The SpotOn collar makes a series of audible warning tones. When your dog approaches the perimeter he will hear an alert tone 10' from the boundary line that sounds like a chirping noise. If your dog progresses past the initial alert tone he will then hear a harsher sounding warning tone 5' from the boundary line that sounds more like a buzzer. Our SpotOn training programs teach your dog to respond to the alert and warning tones before crossing the perimeter, but as all dog owners know, dogs can have a mind of their own. The final warning is a static correction that is intended to quickly get your dog's attention. Your pup's static correction level is determined by following the SpotOn training program in full.