Junior tennis racket head size midplus racket head size 645 cm head size inches 100 sq in stringing 16 x 19 balance 320 mm recommended height 140 155 cm weight unstrung 250 g racket balance head light grip size l0 l1 frame material graphite shape oval frame profile min 24 mm frame max 24 mm length 66 cm length inches 26 technology head graphene season 2017 player novak djokovic additional information the offers may vary in