At one time, firefighters wore pins like these on their dress uniforms. They still wear pins, but this type is no longer available and is pretty rare.
The pin is bright gold metal and features a fire hose with a fire nozzle at each end. The hose is crossed, much like the health ribbons cross today.
As you can see from the photo, it is a tack back pin. It measures 1 inch high by 1 inch at the widest part.