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 305 mm recommended height from 155 cm weight unstrung 320 g racket balance head light stiffness 67 ra grip size l1 l5 frame material graphite shape oval length 685 cm length inches 27 technologies babolat gt babolat woofer system babolat flex carbon additional inform