A SportDOG Dog Fence is made to be tough. SportDOG products are developed with the hunting and sporting dog in mind. Toughness and Durability come to mind when you think of a training collar by SportDOG and you can say that about thier dog fence as well. They are developed to accomodate the largest of yards, an area up to 100 acres. Just what a sporting/hunting dog needs. With a SportDOG Dog Fence features such as built-in lightning protection, low-battery indicator and the ability to add multiple dogs we are confident you will be satisfied.