Black Friday Special! Buy 2 Sets of Head Sonic Pro Edge Tennis String and Get 1 Set Free!! (Valid Nov 21st to Nov 29th Only) Made from uniquely refined co-polymer polyester with a soft molecular construction, Head Sonic Pro string offers superior control and touch for extra pop and spin. This exceptionally durable string offers excellent response and playability that make a real difference. Made for perfect control, without sacrificing touch or feel. Head Tennis String 285503-16-B2G1