Adult tennis racket head size oversize racket head size 677 cm head size inches 105 sq in stringing 16 x 19 level beginner type of racket comfort racket playing properties comfort power balance 345 mm recommended height from 155 cm weight unstrung 260 g racket balance even stiffness 70 ra grip size l0 l4 frame material graphite shape oval length 685 cm length inches 27 season 2017 series babolat game babolat drive colours