Semi Basement General Store 40s us army air force c1 vest 40s us army air force c1 vest Unissued Original U.S. Army Air Force Type C 1 Emergency Sustenance Vest Engineered Garments Navy C 1 Vest Engineered Garments. The C 1 Vest is a versatile, mid weight piece made from a durable cotton poly twill fabric, designed for a standard fit. Crafted in the USA, it features a V neckline, front button and tie closure, angled flap cargo pockets on the chest and waist, a lower back cargo pocket, and a unique back cut out with self tie fastenings. Perfect for layering or adding an extra edge to your look.