M4 Flat Washer Form A DIN125A A2-304 Stainless Steel

This is a plain flat washers form A which denotes the outside diameter of the flat washers The washers are DIN 125A standard which are used to spead the load when tightening fasteners so the nuts and bolts have a good contact surface to assist in keeping the nut or bolt secure.  Washers also take the pressure from just a small space by spreading the load from the component side to prevent wear in the connection of the fastening.

These are A2 stainless steel fasteners which has a preventative measure from corrosion. Ideal for use in damp or wet conditions such as outdoors or in water ingressed manufacturing.  Also bear in mind using different materials can cause fusing through corrosion especially in damp conditions when mixed with aluminium or other none stainless steel metal materials.

More information is available from Central Fasteners regarding fastener details, but its always worth checking with a manufacturer's specifications or drawings if an alternative size, tensile strength or types of washers are used.