Upgrade ANY Pet Containment System offered on MyGoodPuppy.com to 18-Gauge Heavy Duty Boundary Wire AND Heavy Duty 18-Gauge Pre-twisted Wire for larger boundary areas for improved signal strength, rocky soil or above ground installations. Our Heavy Duty 18-Gauge wire is not only thicker on the wire gauge but it also features a heavier coating which is twice as thick as the standard 18-gauge wire sold by other dealers.