A balaclava or ski mask is a form of cloth headgear designed to expose only part of the face. Depending on the style and how it is worn, only the eyes, mouth, and nose, or just the front of the face are unprotected. People wear balaclavas in cold weather to keep warm.
They are now worn for many purposes, including as part of a uniform, to keep warm, and to protect the face from wind, rain, or snow. This latter use means they are often incorporated into winter sports clothing, such as ski boots, snowboards, and ski masks.