It's really helpful to have a picture of the back and side as well as a guess on material so people can get a better idea. Pressed metal vs a casting can drive people in very different directions. That said I suspect it's from a watch fob like this. Maybe pre WWI-ish.
The fob in the link Fourman110 provided (which says "FIRST LAST AND ALL THE TIME) matches yours. The seller says it’s “believed GAR” and that it “appears to be a Civil War Veterans Fob”. Maybe, but I think this also has political connections for the 1884 presidential election.
In 1884 Watkin R, Price and Will J. McCoy wrote a song called “First, Last and All the Time!” which was used as a campaign song for the election that year by supporters of the Republican James G. Blaine and his running mate John A. Logan (they lost). Blaine began his political career as an early supporter of Abraham Lincoln and the Union war effort in the American Civil War.
"We hail the chief of statesmen! The Rupert of debate! The fearless Knight who led the fight for more than twenty years. From East and West and North and South the glorious music rolls. In one harmonious blending the name of Blaine extols…"
...and with a chorus (which provided the campaign slogan):
"Blaine and Logan is our cry! Blaine of Maine and Blaine and Logan, Blaine and Logan is our cry… Victory! First, last and all the time!"