The armor also provides protection against inhospitable environments, including the vacuum of space for a short period of time. Their helmets are fitted with filtration systems for polluted environments, with hookups for incorporating an external atmospheric tank while operating in space or to filter potent toxins. The helmets also include built-in communication system and multi-frequency targeting and acquisition system linked to in-lens displays that provide tactical information, protection from excessive brightness, and vision modes for seeing through smoke, fire and darkness.[1][2]