Rotosound's trademark Swing Bass string set was first produced in 1966. John Entwistle of The Who came to the Rotosound string factory looking for an even, heavy roundwound bass string. Entwistle spent the afternoon there, trying string after string before settling on a set that would become known as Swing Bass 66. A fake jingle for RotoSound can be heard on The Who's 1967 album The Who Sell Out.
