This is a tactile and pleasing lighter which I believe dates to the first world war (1914-1918).
It is 1.75" in diameter with a small steel wheel to the top, and a covered hole to the left of the wheel, which has a pleasant milled edge for easy removal.
Whether this item is made of brass, or is a lighter metal (aluminium or steel) coated with brass or gold, I cannot tell.
In excellent condition for its age, I will point out things which may be important to collectors. The metal does have a deep old patina, and on one side are what look like two small rust splodges. They are clearly visible in the images. The other flat side has light surface scratches, and although some of the photographs make it look like there are dents and dings, there are not. There is general overall wear as one would expect.
The edge of the lighter, where the two sides join, has what seems to be either repair or wear to it. The metal used looks a light lead colour. But it is quite smooth, and I cannot tell if it is simply where the gold/brass has rubbed off, or whether it is where it was repaired with light lead colour metal.
There are no major dings or dents, and to me it seems more like a watch case than a lighter.