... 100% high modulus graphite 4) 70ra Professional 100% carbon fiber tennis racketModel No. Lightning IHead size OS(677cm2/105sq.in.)Length ... 16*19Max tension 24-28kg/53-63lbs 1, Sonata tennis racket uses air dynamics optimization design, bring you better ... fiber process using a special thermoplastic reaction process than ordinary carbon fiber strength, thus improving 18% , stability degree increasing ...