Warm clothing refers to clothes worn, including vests, undershirts, shorts, bras, etc. Warm clothing refers to clothes worn in other clothes, usually in direct contact with the skin, and is one of the indispensable clothes for modern people.

Warm clothes have the functions of absorbing sweat, straightening, supporting the body, keeping warm and not being harmed by pollution from the body, and are sometimes regarded as sexual characteristics. Some warm clothes are more religious. In the Han Dynasty, warm clothes were called heart clothes, in the Jin Dynasty, crotch clothes, dirty clothes in the Tang Dynasty, tube tops in the Song Dynasty, apron skirts in the Ming Dynasty and Chinese-style chest covers in the Qing Dynasty.

One of the earliest natural fibers used in textiles. The history of human utilization of wool can be traced back to the Neolithic Age. It spread from Central Asia to the Mediterranean and other parts of the world, thus becoming the main textile raw material in Asia and Europe. Wool fiber has the advantages of softness, elasticity, strong hygroscopicity and good warmth retention.

Because wool has natural curl, it can form many stagnant air spaces as barriers, which has good warmth retention. Wool has very good stretchability and elastic recovery, special scale structure and good flexibility, so it also has good appearance retention. The processing procedure of thermal underwear wool is very mature, and it will not deform or shrink when worn.