Adult tennis racket head size midplus racket head size 645 cm head size inches 100 sq in stringing 16 x 19 levels professional advanced type of racket all round racket balance 320 mm weight unstrung 300 g racket balance head light stiffness 72 ra grip size l1 l4 frame materials graphite tungsten shape oval frame profile min 22 mm frame max 25 mm length 70 cm length inches 28 technologies babolat gt babolat cortex expert bab