We replaced our two year old in ground fence with this, for our three dogs. I was able to use the wire that we already had buried. I like that you can adjust each collar depending on how stupid.... I mean stubborn the dog is. The beep on the collar needs to be louder. When my dogs are excited, they don't seem to hear it. If it is your first time, I suggest a thicker gauged wire (lower the number, thicker the gauge). This wire can break if it is just pulled on.