Very old dark blue guilloche enamel over copper St. Christopher. This one is for protection during travel by automobile. It is hard to see with the glare and the thickness of the enamel, but there is a 1930s car on the back side. The copper is very tarnished and the jump ring looks to be replaced. It has a diameter of 1/2”. Weight: 1.5 grams. Highly collectible piece.