A stiff square cap with three or four ridges across the crown. Birettas are worn especially by Roman Catholic clergy and are black for priests, purple for bishops, and red for cardinals.

• 法冠帽顶有三或四道边的硬方帽，尤为罗马天主教教士所戴，牧师戴黑色，主教戴紫色，红衣主教戴红色