Strings are plain steel and round wound 80/20 bronze, bluegrass light top / medium bottom gauge 012 016 025w 035w 045w 056w. This alloy is often referred to as brass. It is the original acoustic string alloy selected by D'Addario and D'Angelico in the 1930s. They are often used for recording due to their crisp, deep, and projecting tone; a popular choice for stage and studio.