We automatically upgrade all of our PetSafe Invisible Pet Fence Systems to Heavy Duty poly propylene, boundary wire. Our wire is 3 times thicker and stronger than the wire you will find in any Retail or Online store and has proven to be extremely durable in any climate - even above ground. With many years of hands-on experience, we can ensure our clients get the best system - and best wire - for their individual needs each and every time. Our wire is an 18 gauge solid core, direct burial wire. This same wire is used in commercial irrigation systems, and is designed to last a lifetime. Boundary Kits include Boundary Flags and Boundary Wire. One 500 foot kit is automatically included in every Invisible Pet Fencing Kit. If you need additional wire and flags, we offer two sizes of boundary kits, the RFA-500 includes 500 feet of wire and 50 flags, the RFA-1000 includes 1,000 feet of wire and 100 flags. You can also purchase wire and flags separately so you can get exactly what you need. Use the guide at the bottom of the page to determine the amount of wire needed to enclose your property. Our wire and flags can be used with any pet containment system.