A "found" item, the bag is a heavy canvas World War II-era “MkVII” (Mark Seven) British gas mask bag with the original cotton web strap replaced by a leather strap with a metal adjustment buckle. Interestingly enough, this bag actually did not exist at the time the first three Indiana Jones movies were supposed to take place, given that manufacturing of the MkVII did not start until 1941. However, the bag did exist by 1957, the setting of the fourth movie.
