Developed in the 1970s, the Professional Series® product line were the first classical guitar and lute sets to be offered in a wide variety of gauges. They have been acclaimed by concert guitarists, lutenists and prominent teachers and even used by such great luthiers as Del Pilar, Rubio, Papazian, Van Lennep and Gurian. The Professional Series® have been the preferred strings by a whole generation of great artists including: Laurindo Almeida, Julian Bream, Mario Escudero, Maria Luisa Anido, Sabicas & Rey de la Torre.The Professional Series® strings are still the standard for excellence expected by all serious guitarists. No single set of strings can possibly bring out the finest qualities of every type of guitar or best suit the varied technique and styles of every guitarist. This product line offers some distinctive designs to perfectly satisfy the demands of professional concert performers.A unique design, the 413P Studio set has clear high-density nylon trebles and polished Golden Alloy (80/20 bass) wound basses. The world's first noise-free classical guitar strings, this set has precision polished basses. The painstaking process of polishing wound strings smoothens the surface of the wound string using a stone-grinding method. This helps in eliminating the harsh squeak when shifting positions or playing a glissando. Recently improved with a new construction for increased quality and consistency, the 413P Studio strings are the preferred choice of artists for both concert performances and studio recordings.- Clear nylon trebles produced greater aural transparency and sound projection- Golden Alloy (80/20 bass) wound basses produce exceptional memory for pitch and consistent sound production- Medium Tension- String Gauges: Clear Nylon Trebles: .028 .032 .032; Golden Alloy (80/20 bass) Wound Basses: .029 .034 .041- Made in the USA with American Wire- Packaged using MAP Technology (Modified Atmosphere Packaging) to prevent tarnishing and ensure freshness