Zareba IWTPLB-Z Wood Post or T-Post Insulator, Black Tightly fastens electrified wire to wood, metal and T-posts (1.25 or 1.33 T-posts) For 9 gauge through 22 gauge high-tensile steel wire and aluminum wire, all polywire (both regular and, and polyrope up to  in diameter Molded pin holds wire tightly 25 insulators per bag (Black) Nails are not included