Limited Time Offer Esky Underground Waterproof 2 Shock Collar Electric Dog Fence Fencing System, Fit 20-100lbs Dogs. Over 1.2 Acre Range [1 Year Warranty] 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 Speed Detect Anti-Run through. The faster your dog is moving, the quicker the higher level of intensity is issued. Built-in Lightning Protection. Protects transmitter from power surges caused by lightning strikes Multiple Collar Operation. Add as many collars as you like to contain as many animals you have. There is no limit to the number of collars it can control