Adult tennis racket head size midsize racket head size 613 cm head size inches 95 sq in stringing 18 x 20 level professional type of racket tournament racket balance 340 mm recommended height from 155 cm weight unstrung 289 g racket balance even grip size l1 l5 shape oval frame profile min 21 mm frame max 21 mm length 685 cm length inches 27 technologies wilson amplifeel 360 wilson parallel drilling series wilson control sp