Looking for exceptional comfort, feel, and power? XCEL is the next best string to natural gut. XCEL comes loaded with shock absorbing properties that provide you impressive performance, while being easy on your arm. Your strings are the engine of your racquet. Half of your racquet's performance comes from your strings. Which means choosing the right string is important. We invented tennis string in 1875. And we've been innovating ever since, so you can play your best and enjoy the game more than ever.