Signum Pro is a German brand for over 20 years, produce excellent polyester strings for tennis. Poly Megaforce in Silver colour, soft feel, Poly plasma Pure in White colour softer by 20% than other polyesters on the market.Triton in Lemon colour, granulated for better spin, Hyperion in Black colour, Poly Deluxe in Red colour, Poly Plasma Hextreme for better spin, Tornado with outer spiral for extra spin in Black colour and few more, all in 18, 17, 16, 15L. All polyester strings are mainly for durability, better spin and ball control.Tennis players with wrist, arm or shoulder problems should not use polyester strings in their rackets. Made in Germany.