These metal curtain pole rings have a nylon lining which reduces the noise of the rings on the metal curtain pole. The nylon lining also allows the rings to pass over the pole more easily with a smooth action. They have been designed for use with the Integra Lexington and Brooklyn ranges of double pole systems, specifically for the back pole. However, they are compatible with any 19mm or 28mm curtain pole. Spare curtain rings may be required for particular curtain headings.