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 playing properties control power balance 320 mm recommended height from 155 cm weight unstrung 300 g grip circumference 106 108 mm racket balance head light stiffness 72 ra grip size l2 frame material graphite shape oval frame profile min 23 mm frame max 26 mm le