Junior tennis racket head size midplus racket head size 645 cm head size inches 100 sq in stringing 16 x 19 balance 330 mm recommended height 140 155 cm weight unstrung 250 g racket balance even stiffness 68 ra frame material graphite shape oval frame profile min 24 mm frame max 24 mm length 66 cm length inches 26 technologies babolat cortex babolat gt babolat fis season 2015 series babolat drive colour blue