In winter, many units, such as civil servants in administrative organs, white-collar workers in large companies, sales offices, company marketers, etc., are required to wear suits and shirts during working hours, but the temperature of the working environment is not necessarily suitable. Therefore, clothing should be adjusted according to the ambient temperature, and thermal underwear, vest or warm shirt can be worn under the shirt, which is both warm and does not affect the image, and can be used for winter safety.