The battle gear sets were carded accessory kits that you could use to add on to the existing GI Joe figure, making him more complete. It's interesting that the World War I American soldier has a bacon can (yummy) together with his bread can and condiments can. The mess tin and utensils (fork, spoon and knife) are still being issued in this day and age. After all, you cannot fight a battle on an empty stomach.
Trench periscope, trench knife and sheath. It wasn't until the First World War that fixed trench warfare became the standard form of fighting. The trench system along the Western Front ran for approximately 475 miles, in an "S" shape across Europe, from the North Sea to Switzerland.
The Chauchat (pronounced 'show-shah') was a light machine gun used mainly by the French Army but also by seven other nations, including the USA, during and after World War I. The Chauchat was one of the first light machine guns designed to be carried and fired by a single operator and an assistant, without a heavy tripod or a team of machine gunners.
Overseas cap (also called a garrison cap, side cap or forage cap) and campaign hat. The campaign hat was associated with World War I ground forces of the United States Army. It has since been called Stetson, drill instructor hat, drill sergeant hat, round brown, ranger hat, sergeant hat, Scouts hat, Smokey Bear hat, lemon squeezer and is worn by contemporary US military drill instructors, state police forces, park rangers, Boy Scouts, the Royal Canadian Mounted Police, the Legion of Frontiersmen and others.
Carrier pigeons were used to carry messages in World War I and even in World War II (Carrier pigeons played a vital part in World War II communication for the Invasion of Normandy as radios could not be used for fear of vital information being intercepted by the enemy.) Using pigeons to carry messages is generally called "pigeon post."
Carrier pigeons (homing pigeons) historically carried messages only one way, to their home. They had to be transported manually before another flight. They were selectively bred to be able to find its way home over extremely long distances. "Pigeon mail" can only work when the sender is actually holding the receiver's pigeons.