Gold-plated with 24 carat gold - E1, H2 and G3 are made of high-quality, nickel-plated steel wire and are additionally coated with real gold. D4, A5 and E6 - the core of these strings is tin-plated hexagonal steel, wrapped with gold-plated wire. OPTIMA GOLD STRINGS - probably the most noble strings in the world. Developed and handcrafted in Germany, made from the best materials and designed for the highest sonic demands. This series reflects 75 years of string-making tradition. The result is a premium quality string that has no competition. All strings are coated with real 24 carat gold and are therefore completely resistant to staining or corrosion. Their resistance is up to three times higher than that of ordinary strings and they are suitable for people with a nickel allergy.