Here's a photo of the one I have that's like yours. It's made from a brass nut and a pair of RAF tunic/jacket buttons. It's about an inch or so from flat to flat. Unfortunately, mine is missing a little screw-off cap for the wick.
My guess is yours is also handmade, and done in a similar fashion/materials. They're interesting little lighters for sure, and with such an almost infinite number of various, can make for a nice side collection.
