SportDOG Electric Pet Fence System with Waterproof Collars for Single or Multiple Active Dogs - Includes Upgraded 14 Gauge eXtreme Dog Fence Wire in Multiple Lengths for Use Above or Inground 1000 Feet of eXtreme Brand 14 Gauge Wire Upgrade, for 20+ Years of Reliable Performance Without Degradation Expandable Electric Fence System Can Accommodate Any Number of Dogs with the Addition of Collars Solidly Built and Geared Toward Medium to Larger Dogs, but Can Also Accommodate Dogs as Small as 5 Pounds, with the Right Add-On Collar Unique Correction Levels for All Dogs on the System (5 Progressive Plus Tone and Vibration) Comes with Twice the Length of Boundary Wire that the Other Systems Include, and Can be Expanded to Contain up to 100 Acres