Quick Answer: A durag is a close-fitting cloth tied around the top of the head to protect the hair; similarly a wave cap is a close-fitting cap for the same purpose. Durags may be worn to accelerate the development of long curly/kinky hair, waves or locks in the hair; to maintain natural oils in hair; to stop hair breakage; to manage hair in general; or to keep hair, wave patterns and braids from shifting while sleeping. Durags are also worn as an identity-making fashion choice, popular in Black culture and African-American culture.