Adult tennis racket head size midsize racket head size 626 cm head size inches 97 sq in stringing 16 x 20 level professional type of racket tournament racket balance 310 mm recommended height from 155 cm weight unstrung 310 g racket balance head light grip size l1 l5 frame materials carbon graphite shape oval length 685 cm length inches 27 technologies yonex isometric yonex 3d vector shaft yonex micro core yonex ips yonex super