Strings from the HQ series with round core, designed for acoustic guitar. They are made of Phosphor Bronze material which is a mixture of copper, 5% tin and 1% phosphorus. This combination gives the strings longer life, more precise tone and consistent vibrations. Hand wired round core gives them better density and vintage sound. Strings are better balanced and have better tension. The thickness of the strings: .012, .016, .024, .032, .042, .053.