These hexagon nuts and washers are bright zinc plated for increased corrosion resistance the hexagonal shape of the nut is designed to be driven by a wrench spanner and provides excellent torque when done so the washer distributes the load of a the nut and helps to reduce vibration zinc coatings prevent oxidation of the protected metal to create a longer lasting finish it does this by forming a barrier and by acting as a sacrificial anode if this barrier is damaged zinc oxide is a fine white dus