Television viewers around the world have been treated to the startling sight of correspondents in the Middle East conducting live broadcasts from behind their gas masks. While the image may be bizarre, it points up the very real possibility that citizens and correspondents alike could be exposed to chemical or biological weapons at any time. The mounting threat of Iraqi-led terrorism in the United States has sent gas mask sales soaring at $20 a copy and up; some consumers are spending hundreds of dollars to outfit themselves with chemical suits and bullet-proof vests as well.

How it works: Inhaled air passes through valves into replaceable filters over the cheeks. the filters remove chemical or biological agents from the air being inhaled. The filtered air then passes across the inner surface of the lenses to keep them free of condensation. Air then passes through to the nose, and the exhaled air is discharged through outlet valves.