Dress robes are a formal variety of robes worn by witches and wizards for special occasions. They were similar in style to regular work robes, just differing in colour. For example Harry Potter once wore bottle green dress robes. In the 1994–1995 school year, students of Hogwarts School of Witchcraft and Wizardry were required to bring dress robes in addition to their normal uniforms and equipment. This was due to the fact that the school was hosting the Triwizard Tournament that year, which included the Yule Ball in December.