Yonex Duora 55 Badminton Racket is designed for aggressive level player. The racquet is equipped with Yonex’s DUAL OPTIMUM SYSTEM—an innovative racquet design that features differing frame shapes on either side of the racquet head. Dual Optimum System and Nanometric DR. With These technologies, player will get more repulsion power and impact strength with racket. Its frame is made from HM Graphite, IC Elastomer and Nanometric DR which will provide you better balance during force and control with more accuracy. One side of the frame is box-shaped to put more power into smashes, while the other is aero-shaped to put more speed on returns. Very easy to use with a medium flex shaft and very stable head it enables players with modest ability to attain good power with excellent shuttle control. It contains new grommet hole construction which will provide you more grommet holes for a more high performance stringing pattern. This string tension is 3U 19-26 lbs