The Rotosound RS66LE Swing Bass 66, a 4-string set ranging from 50-110, is the most popular roundwound bass string to date. Rotosound pioneered the production of this string type, debuting in 1962 and revolutionizing the instrument's sound. It remains the preferred choice of numerous bassists, including Billy Sheehan, John Paul Jones, and Geddy Lee. Offered in various popular gauges and scale lengths, the strings are crafted from a distinctive steel blend and a closely guarded manufacturing technique.