These innovative bass strings use copper instead of stiff metals like steel or nickel, resulting in a richer acoustic performance due to the higher density of copper. Additionally, the strings feature a bioplastic monofilament core called Sugar, which has excellent acoustic performance and is produced exclusively by Aquila on a global scale. These strings are truly innovative for at least two reasons. Fristly, they do not use metals like steel or nickel that are stiff, but instead they use copper that is softer and has a higher density and result in richer acoustic performance. In fact, higher the density, better the sounds. Secondly, these strings feature a bioplastic monofilament core called 'Sugar', which is exclusively products by Aquila on a global scale. Sugar has been proven to have superior acoustic performance compared to other plastic materials as evidenced by laboratory measurements.