A snap cap is a device which is shaped like a standard firearms cartridge but contains no primer, propellant or projectile. Snap cap is designed to be a fake cartridge from the very beginning.
It serves the same function as a dummy round, but different in that a dummy is usually made from a real cartridge with its propellant and primer removed (still has the projectile and the casing).
12 Gauge, Aluminum Alloy, Red Anodizing, w/ Sling, 2 Pieces in 1 Pack