MUJI Flannel Pajamas Without Side Seams We've removed anything that might irritate the skin, such as side seams and neck tags. These pajamas are characterized by their soft, fluffy feel. The cotton is organic cotton. The size is women's S. I usually wear M, but sometimes I wear S depending on the product. These are also recommended for those who wear a size M that leans towards S! I wore these for one season, alternating with another pair of pajamas.