The M12 Plastic flanged hex nut for 19 mm wrench 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 (doesnt rust), comes in handy in humid or aggressiv environments (swimming pool, filter and pump rooms, boats) and is resistant to most chemical agents.