High Tech Pet Ultra-Wire Boundary Extension KitNeed more wire? The BEU 500 Boundary Extension Kit gives you 500 feet of custom engineered Ultra Wire, 50 Brightly Colored Flags and 10 waterproof wire connectors. The new Ultra Wire is custom engineered by High Tech Pet Products, for one and only one purpose, electronic dog fence boundary wire. It has electrical and mechanical properties optimized for your dog containment application exceeding even 18 gauge wire performance. The wire is solid core