A balaclava, also known as a balaclava helmet or ski mask, is a form of cloth headgear designed to expose only part of the face, usually the eyes and mouth. Depending on the style and how it is worn, only the eyes, mouth, and nose, or just the front of the face are unprotected. Versions with enough of 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.
variety of uses
Warmth
Thin Balaclavas can be used under motorcycle or snowmobile helmets for warmth in cool or winter conditions.
Sports
Many skiers, snowboarders, cyclists, and runners wear balaclavas in cold weather for warmth. They protect the head, face, and neck from wind and low temperatures and can fit easily under helmets. These sports balaclavas can be full balaclavas, which cover the entire head leaving only the eyes uncovered, or half-balaclavas, which leave the forehead free, but cover most of the head. Key elements of sports balaclavas are that they are warm, windproof, and moisture-wicking.
Racing
Race drivers in Fédération Internationale de l’Automobile sanctioned events must wear balaclavas made of fire-retardant material underneath their crash helmets. In racing events, hill-climbs, special stages of rallies, and selective sections of cross-country events entered on the International Sporting Calendar, all drivers and co-drivers must wear overalls as well as gloves (optional for co-drivers), long underwear, a balaclava, and shoes homologated to the FIA 8856-2000 standard.
Concealment
Balaclavas are in certain contexts associated with criminality as gang members have used them to conceal their identity. In 2004, police in Prestwich, England, began demanding that people on the street remove their balaclavas, describing the garment as “extremely threatening”. In 2012, police in Kent confiscated a copy of the War on Terror board game partly because of the inclusion of a balaclava, stating “could be used to conceal someone’s identity or could be used in the course of a criminal act.”
Military and police
In the Indian subcontinent, balaclavas are commonly referred to as monkey caps because of their typical earth tone colors, and the fact that they blot out most human facial features. Monkey caps sometimes have a small, decorative, woolen pom-pom on top. They are commonly worn by troops on Himalayan duty for protection from the cold.
Source