Gauges 09-11-13-20-09.D'Addario J69 5-String Banjo PB Light Loop Strings are crafted from plain steel and offer a Phosphor Bronze wound 4th string. Phosphor Bronze was introduced to stringmaking by D'Addario in 1974 and has become synonymous with warm acoustic tone.D'Addario is the world's largest manufacturer of strings for musical instruments. Many top guitarists won't play any other brand. Regardless of your playing style, D'Addario has a set of banjo strings that's right for you.