Gamma Poly Z 17G Tennis String Optic Yellow-(GZPZ17OY:SET) The Gamma Poly Z 17G string provides a firm, but responsive string bed for greater control. Ideal for players with full, fast swing speeds, this string also maintains tension well... Size - (See Description) | Color - (See Description) Authorized Gamma Dealer. All racquets are strung and ready for the courts! SEE SELLER DETAILS FOR RETURN POLICY.