This 2" NPT x 2" American Buttress Drum Adapter with 63 mm opening fits most drums. No need to settle for using pumps, valves and other equipment with standard 2" NPT threads in plastic drums with buttress-threaded bung openings.
 
Precision-molded, impact-resistant high-density polyethylene (HDPE) adapter for long service life.
Weather-resistant white EPDM gasket