This is a prototype linear high pressure sodium lamp from the small research & development laboratory of the Polish national lamp manufacturer, COBR Polam. It was manufactured around 1997 as part of a small trial series, but did not go into mass production. The dimensions of the lamp and the type of end caps have clearly been designed to allow it to replace 1500W tungsten halogen lamps of the same length. It is unusual for linear high pressure sodium lamps in that the outer jacket is under vacuum, instead of the usual argon filling.
