The use of halyard leads ensures the proper angle between the halyard and a roller furling unit so as to minimize the possibility of halyard wrap when the sail is furled or unfurled.
Halyard leads are easily retrofitted to an existing mast. Selden single halyard leads are made from chromed bronze, so that the relatively soft bronze will not damage a stainless steel wire halyard. Single models include an insulating plate. Seldon double halyard fittings are stainless steel. The fitting is lacquered on the inner surface to insulate it from the mast.