Adult tennis racket head size midplus racket head size 639 cm head size inches 99 sq in stringing 16 x 15 level professional type of racket tournament racket playing properties comfort power spin balance 340 mm recommended height from 155 cm weight unstrung 304 g racket balance even grip size l1 l4 frame material graphite shape oval frame profile min 24 mm frame max 24 mm length 685 cm length inches 27 technologies wilson