Ski Mask

The  is a full head cloth mask that covers the entire head down to the base of the neck, with an opening in the front for the wearer's eyes. It protects the person wearing it from cold temperatures, as well helps to conceal their identity.

The green and beige balaclava variants are the best for camouflage as they hide your face and blend in with the environment. However, balaclavas can also get wet, causing your character to become colder.

Trivia

 * Balaclavas are named after the town that created them, specifically Balaklava in Ukraine. They were originally made in large numbers during the Crimean War (1854) to protect British soldiers from the nation's bitter cold weather. The garb quickly grew popular among the British soldiers and eventually gained worldwide appeal, especially in colder nations like Russia. Many military forces who specialized in winter combat made use of them and continue to do so to this day. Besides protecting people from the cold, they were also adopted as a means to hide identities in various special forces and mercenary groups.
 * The Balaclavas were added to the game proper in 0.49 update.