This monofilament wire is 12-gauge with a certified breaking load of 500 pounds. A monofilament tensioning system provides a rigid support system for your dog fence. We recommend applying two tight lines of 12 ga fencing wire at the top and bottom edge of your fence will support your installation against fallen tree branches, pawing and chewing from rodents, and the sag that can occur as time passes. A tensioning system also provides support for posts, and holds them straight and upright. Use our monofilament sleeves, gripples, and connector clips to attach monofilament to line, end, and corner posts. All of our monofilament wire is UV-treated for longevity, and black to blend in seamlessly with our fencing products.