Adult tennis racket head size oversize racket head size 697 cm head size inches 108 sq in stringing 16 x 18 level beginner type of racket comfort racket balance 335 mm weight unstrung 255 g racket balance even grip size l1 l4 shape oval frame profile min 26 mm frame max 29 mm length 69 cm technologies yonex isometric yonex aero shape yonex ops yonex shockless grommet system yonex dual shut system yonex super cushion grip season 2