.010 .013 .023w .030 .039 .047 - Set / 24 carat gold-plated acoustic guitar The E1 and H2 strings are made of high-quality nickel-plated steel wire and are additionally covered with real gold . Strings G3 to E6 have a hexagonal tin-plated steel core and are wound with gold-plated winding wire.OPTIMA GOLD STRINGS - Probably the most beautiful string in the world. Developed and handcrafted in Germany from the finest materials and for the highest tonal requirements. This series reflects Optima's 90-year tradition in rope manufacturing. The result is a chain of unmatched premium quality. All strings are coated with real 24 carat gold and are therefore completely immune to tarnishing or corrosion. Their durability is, compared to normal ropes, up to three times higher and they are suitable for people allergic to nickel. The GOLD STRINGS are characterized by a brilliant sound and the typical sound of gold, which Frank Zappa also loved. And of course, Brian May also plays his OPTIMA GOLD STRINGS guitars.