A beauty ring has both a decorative and a functional purpose. They provide a seamless transition between the atomizer and the 510 connector making everything look smarter. Using a beauty ring will also help collect any excess juice from the AFC of your atomizer, protecting the mod by doing so. As an addition it guards your 510 connector against swirl from the atomizer base.
Just place the beauty ring over the connector and screw your atomizer on. The base of the beauty ring is just 0.4mm thick so they should work with all well thought of mods.
NOTE: Beauty rings can only be used on flush connectors. Recessed 22mm catch cup style connectors act as a beauty ring themselves.