The Heavy Duty Lag Corner Insulator is designed for a robust Electric Fence on wood posts and structures. Heavy Duty Corner Lag Insulators are ideal for galvanized stranded steel wire, poly wire or electric rope. This is a High Strain Corner & End Assembly. Each insulator consists of 3/8″ diameter hi-carbon steel bracket, an insulator and a self-locking nut. All metal is zinc-plated.