Pirastro Obligato viola strings are the latest in a new generation of synthetic core strings. Instead of a nylon or perlon core, the viola strings feature a modern composite material of synthetic multifilament fibers. The A string features steel and aluminum winding, the D and G string are silver wound, and the C string is a combination of silver and tungsten. The synthetic core and winding provides complex, bright tones and rich overtones. The core also provides excellent bowing response. The result of six generations of string design and innovation, Obligato viola strings provide a unique tonal balance between warmth and brilliance. Although Pirastro Obligato’s warmth can be compared to the tone of traditional gut core strings, the synthetic core and windings produce more projection and brilliance. Unlike gut core strings however, Obligato’s synthetic core is completely insensitive to temperature change and humidity and provides outstanding tuning stability.