This stove was a modified No:100 & supplied to the Middle Eastern market. It's purpose was to heat pots suspended from tripods or hooks or to heat ovens. The long tube between tank & burner helped prevent the tank being overheated. It comes with a lipstick burner with both silent & roarer caps plus an adapter riser tube to take a regular silent or roarer burner. The box label shows it fitted with a silent burner & no spirit cup. It also comes with a pressure gauge fitted to the filler cap but no note of recommended pressure in the instructions. When it's empty the burner assembly overbalances the stove - so you'd hear a thud when the fuel got low! In the first picture the burner is propped up as there is no fuel in the tank. It was not provided with legs or pan-ring to convert to normal use. The spirit-cup is quite thin gauge brass & has a split in it from new. I saw one on an auction site recently but never seen any others. This one is 'special' to me in more ways than the modification as it was a gift to me from Primus about 10 years ago.