Adult tennis racket head size midplus racket head size 645 cm head size inches 100 sq in stringing 16 x 19 levels advanced beginner type of racket all round racket playing properties control power balance 340 mm recommended height from 155 cm weight unstrung 255 g racket balance even stiffness 70 ra grip size l0 l4 frame material graphite shape oval length 685 cm length inches 27 technologies babolat cortex babolat woofer syste