Drum with plug

A metal container comprising:

• at least one wall defining an interior and an exterior of said metal container, said wall having an opening providing access between the interior and the exterior;
• a collar integrally formed from said wall and surrounding said opening, said collar and said wall being a unitary piece of metal bent both inward and outward in an "S"-shape, said collar including:
• a base having an inwardly projecting portion including and an exterior facing O-ring seat;
• a neck having a first locking element including a plurality of threads formed in said unitary piece of metal;
• and
• a lip;
• a plug sized to fit within said opening, said plug having:
• an upper plug portion having a second locking element including a second plurality of threads cooperative with said plurality of threads of said first locking element to retain said plug within said opening;
• an interior facing O-ring seat alignable with said exterior facing O-ring seat of said inwardly projecting portion of said base;
• and
• an inner plug wall exposed to the interior of said container, said inner plug wall separated from said upper plug portion by said interior facing O-ring seat;
• an O-ring disposed between said plug and said collar on said exterior facing seat, said O-ring having a larger diameter than an inwardmost portion of said exterior facing O-ring seat, said O-ring compressible between said interior and exterior facing O-ring seats to isolate said first and second locking elements from the interior of said container, and said O-ring holding said inner plug wall in spaced apart relation with said collar;
• and
• a support ring having a lower edge attached to said base and an upper edge attached to said lip for strengthening and protecting said neck.