During World War II, undershirts were part of the uniforms issued to the U.S. military, including sleeveless tank tops for summer and long-sleeved wool and cotton blends for winter. It was subdivided into a type and a short-sleeved type made of cotton that can be used for any purpose. Undershirts, which are daily wear, are required to be comfortable to wear and have a quality that can withstand frequent washing. This undershirt is softly knitted using No. 20 combed yarn, and pursues comfort and durability by using double needles from the shoulders to the sleeves and hem. The nostalgic package is reminiscent of government-issued goods of the time.