C.F. Martin Web Site The Darco String Company was originally run by C.F. Martin and the D'Addario family. Martin bought out the D'Addario part of the company in 1970 and has been making the Darco strings since then. Good value, made by Martin. What else can we say? Darco 5000 80/20 Bronze Extra Light Acoustic (10-47) $3.79 Darco 5100 80/20 Bronze Light Acoustic (12-54) $3.79 Darco 5200 80/20 Bronze Medium Acoustic (13-56) $3.79 Darco 9300 NPS Extra Light Electric (09-42) $3.71 Darco 9200 NPS Light Electric Strings (10-46) $3.71 Darco D500 80/20 Bronze Mandolin Strings (10-34) $3.31 String Anatomy 101