Screw-on round post insulator makes it easy to secure your electric fence wire to the electric fence post. These high quality UV-resistant screw-on insulators are designed for all low impedance electric fence controllers and will fit 1/4" to 3/8" diameter posts. They are easy to use simply spin on! This Screw-on round post insulator will accommodate all types of wire sizes up to 3/16”. Available color is Black in a 25 pack.