M4 DIN9021 Plastic large washer for screw M4

The black M4 DIN9021 Plastic large washer for screw M4 is light and sturdy, lighter than its metallic counterpart, and lighter is often better, just ask anyone who is passionate about aeromodelling. Thanks to its dielectric properties, electricians often use these screws, nuts and washers. Not only does it insulate effectively, it prevents corrosion (doesn't rust), comes in handy in humid or aggressive environments (swimming pool, filter and pump rooms, boats) and is resistant to most chemical agents.