The Yonex Ezone 100 series is endorsed by Belinda Bencic and young upstart Casper Ruud, but the slew of enhancements will help players of all levels. The sixth generation Ezone 100SL Tennis Racquet has a new strong, yet elastic material in the throat called M40X. The graphite material improves the racquet’s flex while maintaining the tour level stability which is a hallmark of the Ezone franchise.