I just finished making a new filler for my Optimus 81. I kept the top red cap to make it look like some what looking original. Anyway I had to test it out , as one does. Wife was off at work so I had some left over stew to reheat. A nice slow heat up to simmer. No sticking or burning. They are good for that. So after eating that out of the pan as us heathens do, I had to wash it down with some coffee in the mokka pot. A 25-27 trangia small pot wire support worked a treat. Nothing complex. Haven’t used it for a while. Will run it out of fuel before I put it away. Call it a success. Thanks for looking Bruce