Our Quiet Black Firm Black Synthetic Sheets are of the same material we make our brass instrument washers. The solid tan is the same we make our water key corks from (and older style tenon corks).The “cork” style is the same we make our sax neck and tenon corks from. Sheets without adhesive can be glued up with contact cement. When working with adhesive backed sheets, you can improve the bond by applying contact cement to the part you are “corking”.