Whether you've moved to a bigger backyard, have another dog to contain and need more space, or if that growing canine companion just needs more room to roam, this wire and flag accessory kit lets you expand the boundaries of your SportDog electric dog fence with ease. Designed for the SDF-100 In-Ground Fence System and compatible with Petsafe's Standard and Deluxe Radio Fences, this expansion kit comes complete with 50 boundary flags and 500 feet of wire. The 500-foot roll of standard 20-gauge, stranded wire lets you add 1/4 of an acre to existing doggie play space. Fifty flags designate the new area clearly. SportDOG Brand® is the most recognized brand in the electronic dog training category. Our products are known not only for their quality, but also for being the best value for the dollar out there.