Product Description D'Addario is the world's largest manufacturer of strings for musical instruments, having a reputation as a manufacturer with unsurpassed quality. The innovative packaging developed by D'Addario does not harm the environment, protects the strings from contamination and corrosion. All D'Addario strings are manufactured in the USA on unique proprietary equipment, under the control of a proprietary digital quality system. From the Manufacturer D'Addario's most popular acoustic bass set, EPBB170 provides a rich, deep and projecting tone.Phosphor Bronze was introduced to string making by D'Addario in 1974 and has become synonymous with warm, bright, and well balanced acoustic tone. D'Addario Phosphor Bronze strings are precision wound with corrosion resistant phosphor bronze onto a carefully drawn, hexagonally shaped, high carbon steel core. The result is long lasting, bright sounding tone with excellent intonation.D'Addario, the world's largest manufacturer of musical instrument strings, is known as The Players Choice with a reputation for unsurpassed quality and consistency. D'Addario's innovative packaging reduces waste and provides protection from corrosion. All D'Addario strings are manufactured in the U.S.A. using proprietary, digitally controlled, state-of-the-art machinery for unmatched performance, set after set.