Thank you for your question regarding the model 613. The metal ring you are referring to is essentially a beauty ring or trim collar for the inside wall to cover up a cut-out hole. It will give the installed vent a finished look and the hole around the pipe a more aesthetic appeal. It offers a tight fit for security. Should you have further questions, please contact our Technical Support directly at 800-637-1453.
Date published: 2017-03-31