Adult tennis racket head size oversize racket head size 658 cm head size inches 102 sq in stringing 16 x 20 level advanced type of racket all round racket balance 340 mm recommended height from 155 cm weight unstrung 249 g grip circumference 109 111 mm racket balance even grip size l3 frame materials basalt carbon shape oval frame profile min 23 mm frame max 23 mm length 692 cm length inches 27 technology wilson blx seri