Thought I would add this one to collective wisdom. Picked it up a few months back much like you see it, missing the legs and top burner plate but otherwise complete. All seals were old and needed replacement. Judging from their composition and dryness they were either original or from the era. The nrv was cork. Runs well now. From reading the previous posts I am judging it to be 1920's? The clues are I hope are captured in the photos but I would be willing of course to answer any questions. Clues: - Spirit cup has a dimple - Air release valve: situated in the body with "Optimus" embossed on one side and "Sweden" on the other side - Filler cap embossed: A/B Optimus Stockholm Made in Sweden - Pump cap embossed: Made in Sweden - Body: imprinted on the top: Optimus No 45 Made in Sweden (no other writing) - Stamp on the underside: A B OPTIMUS STOCKHOLM MADE IN SWEDEN I am sorry no flame shot but it produces a nice blue flame and a magnificent roar. It sadly lives with three cheap replacement legs and a tinny top plate but I hold out hopes of someday fining a cast iron top plate. Until then it still does a wonderful job of cooking a meal. In respect to its age and due to the fact I found no corrosion to warrant it, I choose not to polish the fine old patina on it. I do like shiny brass but this one has earned it's grey hair.