Fi-Shock IW5XNY-FS Yellow Nail-On 5-Inch Extender Insulator with Barn Nails Fastens electrified wire to wooden posts without losing energy through the post Extends the wire 5" from the wooden post For 9 gauge through 22 gauge high-tensile steel wire and aluminum wire, all (both regular and heavy duty) and up to " in diameter Includes Barn Nails Packed 25 per bag