J. D'Addario & Company, Inc. is the largest maker of strings for musical instruments in the world. J. D'Addario also designs and manufacturers a collection of music-related accessories, including guitar straps and accessories, marketed under the Planet Waves brand name, and drum heads through its ownership of Evans Drumhead Company. A vertically integrated enterprise, the company designs and builds its own automated manufacturing equipment, operates its own printing press, and maintains a large research and development department.
Ernie Ball was the first to offer rock strings with the creation of Slinkys, and further revolutionized the market by offering guitarists Custom-Gauge single strings. The Ernie Ball company also produces Music Man guitars and basses, volume pedals, and other accessories.