Hex flange nut has a wide flange that is integral non spinning washer that distributes pressure of the nut flange over a larger area of the surface. Flange nuts have serrations to lock the nut in place and to prevent back-off or loosening by vibration. Please Note: the serrations will scratch the surface. There are non-serrated flange nuts but are not widely available.
A2 Stainless Steel is the Fastener Industry Standard for Metric Sized Fasteners in Stainless Steel. A2 Stainless Steel is durable and corrosion resistant making Metric Nuts in this selection suitable for exterior and harsh environments.
Hex Flange Nuts Listed Below Feature Serrated Washers.