Head Synthetic Gut PPS Tennis String Set-17G Gold Combining all around playability with additional performance, Head Synthetic Gut PPS provides a bit of everything all in one package. Named for the PowerStrip Technology, which is a Polyphenelyne Sulfide Strip, this string provides added resilience and elasticity for extra power... Monofilament Polyamide Center . FEATURES: Elastic And Power . FEATURES: Added Durability. FEATURES: Synthetic Gut PPS Strings Size - (17G)_____Color - (Yellow) Authorized Head Dealer. All racquets are strung and ready for the courts! SEE SELLER DETAILS FOR RETURN POLICY.