Augustine produces 3 different series of classical guitar strings. The most well-known sets have identical high strings in normal tension, the difference lies in the tension of the low strings. All GOLD strings consist of a golden brass winding on the low strings and always in light/normal tension. The IMPERIAL series consists of precision round strings in the high strings in high tension. All Imperial sets contain the famous low strings and with different tension. The REGAL series consists of precision round strings in the high strings in extra high tension. All Regal sets contain the famous low strings and with different tension.