ARMan

New to this great forum. I refurbish AR speakers. I've done sets of 3a's, 2ax's a set of 4ax's and now I am refurbing a really cherry set of AR12's. I have a question concerning the felt(?) that goes around the outside of a driver (woofer). I guess it's a gasket? Sometimes they are a felt like substance, sometime they are rubber like. What are those called and where can you purchase? They don't come with typical refoam kits from places like Simply Speakers and I don't see them on their list of products. Any help is appreciated.