Adult tennis racket head size midplus racket head size 645 cm head size inches 100 sq in stringing 16 x 19 level professional type of racket tournament racket playing properties comfort power spin balance 320 mm recommended height from 155 cm weight unstrung 300 g racket balance head light stiffness 72 ra grip size l1 l5 shape oval length 70 cm length inches 27 season 2017 series babolat aero colours green black additional