La Bella 413P Studio Recording Strings Medium Tension Classical Guitar, Full Set A unique design, the 413P Studio Professional set has clear high-density nylon trebles and polished wound basses. The world's first noise-free classical guitar strings, this set has precision gold polished basses. The painstaking process of polishing wound strings smooths the surface 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 artist's for both concert performances and studio recordings.Note: The technique of polishing takes away the silver plating slightly exposing the copper wire. As a result, the color may vary from silver to brown to gray.