Officially designated ‘Coat, Mans, Combat, Tropical’, Natick Labs originally designed the US Army tropical combat jacket and trousers in 1962 for the Vietnam War. The single-breasted jacket was made from 5½ oz. wind-resistant cotton poplin in OG-107 and featured two slanted chest cargo pockets and two lower cargo pockets. The design also boasted epaulets, waist take-in tabs, pen pockets behind both chest cargo pockets and an inner gas flap that was designed to prevent chemical agents leaking through the front button closure. The tropical combat uniform was ideally suited to the Vietnam War because it was both lightweight and quick drying, but it's exposed pocket buttons had a tendency to get snagged in the jungle so subsequent versions were developed. TSPTR removed the epaulettes and gas flap and shortened the length to create a less fussy hybrid. The same weight (5½ oz) and quality poplin as the original has been reproduced and then overdyed using natural dye in their signature Aloha print.