16-22-30W-48-58-70 Lenth 43 inches Phosphor Bronze wound strings were introduced in the early Seventy??s and have become the most popular acoustic string. Phosphor bronze wire is made from approximately 92% copper, 7% zinc and 1% phosphorous. Phosphor Bronze provides nice highs and lows pleasant subtle overtones. Phosphorous is used to help reduce tarnish and corrosion.