Yonex Poly Tour Strike 16L 1.25 Tennis String Packages Cool Black : Attack each ball with the new Yonex Poly Tour Strike 16L 1.25 tennis string is a snappy, polyester monofilament designed to provide long-lasting tension hold, durability and supreme power. This string helps provide players with impressive power as well as precision. Monofilament core with a high polymer polyester finish. Delivers precision, power, and overall excellent performance.