Primus first lamp model. There's no date stamp seen on this one, which possibly might indicate a manufacturing year just before 1911. Anyway, it's in that area these were made; around 1912-14 (see Nils´ lamp in this gallery.) It uses a Lux-type burner and vaporiser for an upright, rigid mantle. The spirit cup has a deep indentation to keep enough alcohol burning for starting the lamp when the preheating has finished (as seen on the last three images). I used a globe I have on a Lux lamp to give it a more complete look. No surprise, Primus has choosen to use also the exact size of shadeholder as Lux. It fit like a glove!