Adult tennis racket head size midsize racket head size 626 cm head size inches 97 sq in stringing 16 x 19 level professional type of racket tournament racket balance 305 mm recommended height from 155 cm weight unstrung 340 g racket balance head light grip size l2 l4 frame material graphite shape oval frame profile min 21 mm frame max 22 mm length 685 cm length inches 27 technology wilson amplifeel technology season 2016