Field Guardian W-Style Screw on Polywire Round Post, Black Fits round posts up to 14mm (0.55 inches) diameter or can be nailed to a wood post Insulator slides down the post to install Screw down to desired tightness 25 per pack Main color is Black Fits round posts up to 14mm (0.55-inch) diameter or can be nailed to a wood post Insulator slides down the post to install Screw down to desired tightness 25 per pack Main color is black