A balaclava , also known as a balaclava helmet or ski mask, is a form of headgear that covers the whole head, exposing only the face or upper part of it, and sometimes only the eyes, mouth and nose, or just the front of the face are unprotected. Versions with a full face opening may be rolled into a hat to cover the crown of the head or folded down as a collar around the neck. Modern balaclavas are used in outdoor winter sports such as skiing, snowboarding, and snowmobiling to protect the face from wind and maintain warmth. They are also popular among motorcyclists.