Diadem Evolution is a polyamide monofilament with a low friction silicone based coating. This non-polyester monofilament is incredibly responsive and comfortable with long lasting durability. Designed to handle the sharp edges of our sharp polys this string offers precision, comfort, and easy power. This 660ft reel is ideal for the player that frequently re-strings their rackets and is looking to save money by buying in bulk. Strings 17-19 rackets. Rated as a top string by TIA.