I believe those are still highly regarded for their simplicity and durability. I think of that design as a Svea 123.I really like that design.
I see it listed as the Optima or the Svea, but the instruction sheet (and yes, it has the original instruction sheet!) says Optima.Jie, I have seen them on eBay and a few specialist sites. I'd also suggest checking Army/Navy surplus stores since this was an actual issue stove. I can't say much about it's longevity as I just got it, but my father has been dragging it around for well over 40 years without use and it still fires up without a problem.Def