The most important part of an invisible fence systems the wire. When considering what ground dog fence wire to purchase, the first thing, and most important part of your decision, to consider is the gauge of your underground fence wire. The gauge of the wire you select determines the durability and work-ability of the pet fence wire, and the expected lifetime of the system. Often when you buy a new system they supply small yellow 20g wire, however consideration should be put into upgrading this wire to a thicker more robust wire before you spend hours installing it. As over time that small 20g yellow wire that you got when you brought the kit will break. Which means you may need to spend countless hours finding and repairing breakages- this is why we sell a larger stronger 14 gauge wire.