Extra Hard Tension strings for classical guitar. Master Series Classical Strings provide superior tone, excellent feel, tuning stability, and extended life. They‘re used and loved by classical performers worldwide. For rich bass tone and a smooth feel, Master Series bass strings are precision wound with the highest quality Silver-Plated Copper wire wrapped over extremely durable, stranded nylon cores. The treble strings are made from the finest grade polished nylon. Features set of six strings. String size: .028 / .032 / .040 / .030 / .036 / .045.