D'Addario was the first to use Phosphor Bronze in acoustic guitar strings in 1974. Today, Phosphor Bronze is considered the standard in acoustic guitar strings due to its wonderful tonal balance and warm sound. The innovative Phosphor Bronze acoustic guitar strings are precisely wound with phosphor bronze winding wire over a high-carbon steel core, providing tonal flexibility suitable for all acoustic styles and genres. The 10-47 Extra Light gauge strings are easy to play and bend.