The conductor that carries the pulse around your perimeter — galvanised wire, high-tensile wire, polywire, and polytape, chosen by visibility, distance, and budget.
Fence wire is what actually carries the energizer's pulse around your boundary, so the right choice depends on how far it needs to run, how visible it needs to be, and how much handling it will see over its working life.
Longer perimeters generally favour galvanised or high-tensile wire for durability and lower long-term cost per metre. Shorter, temporary, or frequently-moved paddock divisions suit polywire or polytape for ease of handling. See the fence wire buying guide for a full comparison, or use the wire calculator to work out how many rolls a given perimeter needs, including a sensible waste allowance.
Wire needs insulators at every post to stop the charge leaking into wet timber or steel, and connects back to an energizer to complete the circuit. Pro Fence and Tiron both supply wire ranges through Pemall — see the Brand Centre to compare.