The Rotosound RS665LDN Swing Bass nickel bass guitar strings are a nickel-coated version of their best-selling Swing Bass 66 strings. This is the roundwound string that James How and John Entwistle perfected into what was to become the industry standard. The bright, punchy, high-energy sound of Swing Bass 66 strings is a major part of early rock music history and brought the bass player from the back line to the front of the stage.