Ernie Ball Nickel Wound 6-string Baritone Electric Bass Strings are made from nickel plated steel wrapped around a hex shaped steel core wire. The plain strings are made of specially tempered tin plated high carbon steel. Each bass guitar string produces a bright, balanced tone and manufactured with small ball ends like guitar strings, not large ball ends used on traditional electric bass strings. These sets are optimal for A-A or B-B tuning combinations and are a perfect match for their hybrid baritone instruments. Gauges .013, .018p, .030, .044, .056, .072.