Oumers Electronic No Bark Collar Anti-Bark collar Stop Bark Collar Anti Bark Shock Collar , with 7 Levels Button Adjustable Sensitivity Control, Effective, and Humane Dog Barking Control collar Keeping a Quiet Environment At Home/Indoor, For Small / Medium dogs At the first bark,this Anti-bark Collar applies a short warning tone.if a second bark occurs within thirty seconds,a more intense tone is sounded.From the third bark a more intense tone is sounded along with a short,mild shock. 7 sensitivity levels (1-7) adjustable for the different size of dogs barking through the "+" /"-" button The stimulations repeat through 7 correction levels, the intensity gradually increases until the dog stops for thirty seconds. If the continuous stimulus reaches the 7 levels, then the Collar will stop working for 1 minutes to protect the dog Humane, cost-effective and harmless to your dog. Generally recommend for small/medium dogs Don't encourage to use it for puppy, especially below 8 lbs, but you maybe can have a try carefully. If the dog is too small, you must use it under the guidance of the master to avoid unnecessary harm to your dog, because the stimulation for the puppy will be a little strong