A ski mask, also known as a balaclava, is a headgear that covers the head, face, and sometimes neck, typically made of stretchy material like fleece or knitted wool. It is designed to provide warmth and protection in cold weather, often used in skiing, snowboarding, snowmobiling, and other winter sports. Additionally, ski masks are used for various outdoor activities where facial protection from cold, wind, and sometimes dust or debris is necessary.