Gauges 45-65-85-105. Pressure wound stainless steel. Long scale. Solo Bass is made by rolling the wire as the string is being made. This string has 3 advantages over the conventional roundwound: a smooth feel, ideal for fretless bass and studio work; no finger noise/reduced fretwear, and it retains the brightness of the roundwound string. Rotosound is famous for their high quality electric bass strings.