A long coat with no vents will slow a man down. For a soldier, making him an easy target for machine guns and snipers as he goes over the top of his trench into No Man’s Land
Trench coats should have a removable D-ring belt.
Sometimes called a gun flap, this extra piece of fabric covers the right side of a man’s breast.
Many trench coats do not come with insulated linings. These are reserved for tropical climates.