It's not just a pair of stockings that have this effect. The stockings worn by girls are divided into winter clothes and summer clothes. In summer, a thin layer of stockings is cool, but in winter, it is velvet inside and looks like stockings outside, so it is warm in winter. My rural children didn't know this at first. Later, I went to college and there were more people around me. Seeing other girls dressed up and others wearing too much, I realized that the so-called stockings are warm in winter and cool in summer.