Please Note: on the above picture on the right for size comparison: Left: 12.7x108mm vs, Right .50 BMG (USA’s Browning Machine Gun) or 12.7x99mm.

One Cartridge not a Box! 12.7×108mm Soviet Heavy Machine Gun cartridge, new production by Tula of Russia, loaded with new Tula brass cases, with “Tulammo 12.7x108" Head-Stamp and loaded with a non-corrosive, Berdan Primed primer, and 680 grain FMJ (Full Metal Jacket) projectile, which is attracted to a magnet.

History of the 12.7×108mm Soviet Heavy Machine Gun cartridge:
The 12.7×108mm cartridge is a heavy machine gun and anti-material (anti Tank) rifle cartridge introduced  in 1930 in former Soviet Union, and use in World War II by the Soviet Union and the former Warsaw Pact. It is still used today by Russia and other countries.
The American .50 BMG (Browning Machine Gun) is 12.7x99mm a little shorter the 12.7x108mm.