T-shirts, also known as T-shirts. At first it was underwear, actually a lapel half-open collar, that later developed into a coat, including T-shirts and T-shirts in two series. There has been a divergence of views about the origin of T-shirt names, a claim that Dockers who unloaded tea in Annapolis, Maryland, in 17th century wore the short-sleeved clothes, which were abbreviated as "T" and called T-shirt T-shirts; and the second was that in 17th century, The British sailor was ordered to add short sleeves to his vest to cover his armpit hair to avoid unsightly; there was also a claim that the sleeve and upper body formed a "T" glyph, that is, the garment is a T-shaped suture collar, hence the name. In the 1913, the United States Navy stipulated that sailors wore sailor-collar short-sleeved white sweatshirts in their overalls, one of the reasons being to cover the sailors ' bushy chest hair. T-shirts used a wide range of raw materials, generally cotton, hemp, wool, silk, chemical fiber and its blended fabrics, especially cotton, hemp or hemp cotton blended as a good, with breathable, soft, comfortable, cool, sweat absorption, heat dissipation and other advantages.