Use these posts with 5' high dog fence and 6' high fence. These post are hard enough to pound through rocky soil. Our steel Freedom Fence Posts are made from recycled railroad rails and are black-coated. These strong, steel, posts offer the same quality workmanship that you expect from Deer Fence USA at a lower cost than our Ultra Deer Fence Post Kits. Easy to install, these posts are driven into the ground using a sledgehammer and are to be spaced 10'-12' apart, for best results. No Driver Cap or sleeves required!