Plastic preform with stepped neck finish

A preform for forming a blow molded container, which comprises:

• a base, a cylindrical sidewall projecting upwardly from the base, a neck finish projecting upwardly from the sidewall and having an opening to the inside of the preform;
• wherein the neck finish includes an inwardly oriented stepped area adjacent said opening;
• said stepped area including an upper, outwardly extending flange which borders on the opening, said outwardly extending flange having an outer surface and an inner surface;
• a downwardly extending flange extending downwardly from the inner surface of the outwardly extending flange and essentially perpendicular to the outwardly extending flange, and having an upper portion connected to the inner surface of the outwardly extending flange and a lower portion opposed to the upper portion;
• and
• a lower inwardly extending flange connected to the lower portion of the downwardly extending flange and extending inwardly of said downwardly extending flange and essentially perpendicular to the downwardly extending flange, wherein the lower inwardly extending flange has an inside surface and an outside surface and the outside surface terminates at the lower portion of the downwardly extending flange.