Waterproof 2 Dog Electric Shock Containment Pet Dog Fence System Collars Safe Up to 5000 square meters range, Over 1.2acre.Fits for most dogs with weight from 20-100lbs, neck size 1-18 inches. Pulsed Proportional Stimulus The closer your dog sets to the boundary, the more intense the shock will be. Progressive Tone Stimulus A warning tone will be issued first, then a shock stimulus if your dog continues to move closer to the boundary Variable Field Width Control Allows you to precisely control the width of the signal field Audible and Visual Wire Break Indicators Should your buried wire ever break, a loud sonic alarm will sound accompanied by a flashing light