Oscar Schmidt Autoharp A-Model String Set of loop end strings is for models OS73B/OS73C black re-issue autoharps and vintage autoharps built before 1967. This set includes 36 strings, individually wrapped and labeled for your convenience. These strings have a loop end that slips over pins in the side of the autoharp down by the bridge. In addition, the pins are covered with a plastic cover to prevent them from snagging on clothing.