flak jacket
protective vest or jacket containing overlapping plates of steel, aluminum, or bonded fiberglass, to protect against shell fragments and shrapnel
en-US/ˈflæk ˈd͡ʒækət/
en-GB/ˈflæk ˈd͡ʒækɪt/
protective vest or jacket containing overlapping plates of steel, aluminum, or bonded fiberglass, to protect against shell fragments and shrapnel