First Downs ex. Joe Shmo 13 FD
It means First Down
On a ring, FD 925 means that the jewelry is sterling silver. However, the FD is simply the initials of the manufacturer.
FC=Fuel Cell FR=Fire Retardant FD=Final Destination
What does a ring that has the markings in this order 925 fd and then CM on the opposite side!
functional design specification