Metric sizes are: M10 x 21 x 1.6mm | M16 x 30 x 1.6mm | M20 x 37 x 3mm

Sold individually.

Flat washers are used to spread the load of a screwed fastening such as a screw or nut. Flat washers may be used when the hole is a larger diameter than the fixing nut and to prevent damage to the surface being fixed. Washers are important for preventing galvanic corrosion, particularly by insulating steel screws from aluminium surfaces.