This WWI Tracer Cartridge Box is a reproduction of the 30 caliber ammo that was normally used in WWI aircraft. The Ammo box is empty. It’s sealed with a label and can be sliced open for use.
Tracer rounds contain a pyrotechnic charge that can be used for targeting. Typically, tracer ammo is loaded into an ammo belt in a 4-1 ratio. Tracer rounds could also be used by the infantry for marking targets.