Plain Washer Form C HDG

This is a Form C flat washer sized for an M12 bolt, made to the ISO 7089 standard. An M12 washer under this standard has an inner (clearance) diameter of 13.0-13.27 mm, an outer diameter of up to 24 mm and a thickness of 2.3-2.7 mm, giving a wide bearing surface that spreads the clamping load of the bolt head or nut over the surrounding material. The hot-dip galvanized steel finish gives long-term corrosion protection where the washer is left exposed to the weather, as it typically is in a ground-mounted or rooftop solar mounting system. Washers of this kind are used wherever an M12 fastener needs a flat, load-spreading seat, such as under a nut or bolt head on a mounting frame or foundation connection.