Wilson Champion's Choice contains: Wilson Natural Gut 16G
and Luxilon Alu Power Rough 16G.
Polyester Hybrids. Featuring amazing power and control with optimal comfort and durability, the combination of the world's best monofilament with premium natural gut has made this string the fastest growing hybrid on the pro tour.
As used by Roger Federer.
Wilson Natural Gut: Natural gut is highly responsive and uniformly smooth giving the best combination of power and control. Even with all of the highly advanced methods for making synthetic strings, nothing compares to the qualities of natural gut string.
Luxilon Alu Power Rough: A playable string designed for players who want more durability with amazing power and control and a rough texture for extra bite on the ball for superior spin potential.