D'Addario J69B 5-string banjo sets are designed for banjos requiring ball end strings. Each string has a ball end instead of a loop end. J69B 5 strings are made from plain steel and offer a Phosphor Bronze wound 4th string. Phosphor Bronze was introduced to string making by D'Addario in 1974 and has become synonymous with warm acoustic tone. J69B - 09, 11, 13, 20, 09.