This Field Guardian Heavy-Duty Tie-On Corner/End Electric Fence Insulators are a dead end or corner insulator with very good mechanical properties that is specially designed for fences using polywire, polyropes, aluminum wire, high tensile steel wire and 1/2 in. polytapes. The corner insulator is very helpful for when you need to run wire or polyrope but don't want to damage your posts. Its wire tie-on attachment method makes these electric fence insulators easy to set up. The dead end insulator is made from high density polyethylene for incredible durability.