New 19+ Daddario Half Round Electric Guitar Strings. D'addario half rounds electric guitar strings are round wound with stainless steel and then precision ground leaving the outer surface smooth and d'addario, the world's largest manufacturer of musical instrument strings, is known as the players choice with a reputation for unsurpassed quality. They are round wound with stainless steel and then precision ground, which. D'addario ehr half rounds are truly unique feeling electric guitar strings.