These spirit burners are manufactured by Trangia and are pretty much the standard when it comes to these types of burners. They run on denature alcohol which can be found just about every where from the paint section at the hardware store to gas stations.They are compatible with the Fireant and will snap into the slot at the top of the stove. They come with a lid and simmer ring. When the burner is in the Fireant there isn't quite enough room for the simmer ring to work properly, however it is useful to snuff the flames when you are done cooking.
On occasion we get Esbit Spirit burners (almost exact clones) but these are Trangia.