D'Addario's EPBB170-5 offers a rich, deep, and penetrating sound for all 5-string acoustic basses. Phosphor bronze was introduced by D'Addario into string manufacturing in 1974 and has since become synonymous with warm, bright, and well-balanced acoustic tone. D'Addario phosphor bronze strings are precisely wound with corrosion-resistant phosphor bronze around a carefully drawn, hexagonally shaped high-carbon steel core. The result is a durable, bright-sounding tone with excellent intonation. These strings are specifically designed for use on 5-string acoustic basses and are very popular due to their warm, bright, and well-balanced acoustic sound. They come in environmentally friendly, corrosion-resistant packaging to ensure that the strings remain fresh. Made in the USA for the highest quality and performance. String gauges: Phosphor bronze wound .045, .065, .080, .100, .130.