Brass or copper cap

[cudamark]

What is this brass or copper cap from? It says L.P. Co. St. Louis on top with a star in the middle. Not threaded but the edge is knurled at the top. Very thin metal that may have been chrome plated at one time. Age? Thanks.

 

[Ant]

The front of a snap button, like on a letterman jacket or on the strap to tighten the gauntlet strap on gloves, etc.