Vcall Pet Dog Training Anti Bark Electric Collar Bark Solution Shock Collar with 7 Levels Adjustable Controller HARMLESS AND EFFECTIVE - Our No Bark Dog Training Collar has been designed to be absolutely safe for your pet, while also giving them a good warning to stop their bad barking behavior. GREAT FOR ALL SIZES - This collar works on tiny dogs of 8 pounds up to big 120 pound giants. The sound it emits and the gentle shock work together to teach your dog better behavior. EASY TO USE - As soon as your No Bark Collar arrives, simply slip it around your dog's neck and the system will work automatically. EASY ADJUSTABLE SENSITIVITY LEVEL - 7 levels sensitivity levels (1-7) adjustable for different size of dogs barking and specific environments through the "+" & "-" buttons. PROGRESSIVE EFFECT:The collar will only give a very soft shock and sound at the first bark and will only intensify if the barking continues. Still, the shock never exceeds inhuman levels.