Phosphor bronze set for Acoustic/Western Guitar 6-string;Phosphor Bronze is a high quality copper alloy with 5% tin and 1% phosphor.;Balanced, warm, earthy sound and long durability. Visually, the strings are recognisable by their darker colour;Treble strings: Steel plain, bass strings: Steel core hexagonally wound with phosphor bronze;Light Tension, .012/.016/.024w/.032w/.042w/.053w;