Subject: U.S. Army military field shirt with internal gas protective flap Color: Olive drab green Material: Wool or wool‑blend flannel (material content tag not present) Tag size: 15-32 (Mens) Features: Button front; two chest flap pockets; button cuffs; curved shirttail hem Feature: Interior flap with stenciled text “GAS FLAP” Era: Vintage WWII 1940s military style Labels/Markings: Size tag reads “15-32”; interior stencil reads “GAS FLAP” Notes: Vintage item; sizing can vary by era—please review photos to assess fit relative to a similar shirt.