It's easy to get paralyzed by the offerings out there, especially if you have no experience with purchasing flags. So here is a simple breakdown of the chief flag fabrics and their pros and cons, so that you can choose what flag best meets your needs.
Retainer rings are a necessary component to internal halyard systems. Without them, the flag would not be attached to the pole at all, and would be flapping in the wind. In the last few years, owners of external systems have been utilizing retainer rings as well, as they serve several purposes, and often address multiple issues at once.