The Bark Boss Rechargeable No-Bark Trainer from DT Systems is the perfect solution to help train your dog to stop unwanted barking. The collar can be programmed for a beeping tone only or a beeping tone warning with the e-Stim shortly following. How It Works• Put the collar on the dog (collar is adjustable from 7" - 27").• Adjust the easy clip buckle collar so that the collar is snug around the dog's neck.• Turn the easy turn dial to the needed level (from 1-8) or to "T" for beeping tone only.• Stimulation level will depend on size and temperament of the dog.• The middle post on the collar senses the vibration from the dog's vocal cords.• It will not activate from loud noises or other dog's barking â only from your dog's barking.• The sensor picks up the barking vibration and activates the beeping tone, followed by the e-Stim.• This gets the dog's attention, and they begin to associate this with the barking so they stop the unwanted barking. Collar adjusts from 7"" to 27"" Stimulation levels from 1 to 8 depending on size & temperament of dog Will not activate from loud noises or other dog's barking only from your dog's bark | DT Systems Bark Boss Rechargeable No Bark Trainer