This drawcord elastic is comfortable elastic with a built-in cord that can expand to twice the elastic length * Made of 66-percent polyester, 34-percent rubber and 100-percent polyester drawcord * Machine washable and dryable in temperatures up to 200 degrees fahrenheit * Insert into casing and pull cord through a buttonhole * Cord can be hidden on the wrong side of fabric or can be exposed by pulling through to the right side