This is an Elixir Nanoweb coated phosphor bronze acoustic guitar single string. Phosphor bronze has a balanced, full, and clear tone.

The consensus among many musicians is that phosphor bronze strings offer the most sensitive, expressive tone that brings out the very best in guitars – virtually taking them to a higher level of play. However, that tone can be short-lived. Elixir Strings has solved this classic conundrum by applying an ultra-thin layer of NANOWEB Coating to protect the string windings hence preserving the coveted phosphor bronze tone.