ompanies that manufacture things like gas masks and chemical-repellent bodysuits used to sell their wares almost exclusively to the military and the police. After 9/11, however, these companies have suddenly found themselves marketing products to individual consumers. Ads for palm-size gamma-radiation alarms now appear regularly on cable channels; specialty stores are filled with strange, disturbing new items like miniature ''food screeners'' (which check for suspicious ''additives'' and ''residual solvents'') and ''tote 'n' go'' emergency-survival kits (which feature 3,600-calorie emergency food rations and sanitation bags). Anxious Americans have clearly decided that stockpiling batteries and freeze-dried vegetables isn't enough, and the emerging ''homeland security market'' is ready to serve them.

Wary of airport security? You may feel a bit safer if one of your carry-ons is a $600 shoulder bag that deploys as a ballistic shield. Simply flip up the outer shell, made of abrasion-resistant nylon, and you have yourself a 14-by-30-inch panel of bulletproof armor. The bag also has plenty of room for other goodies, like a hand-held nerve-gas detector that runs on ordinary batteries. And the bag's mobile-phone compartment is perfect for storing the cute, Taiwan-imported stun gun that's disguised as a cellphone. It delivers a 180,000-volt jolt from its antenna, enough to knock an assailant flat. Nervous about opening mail from strangers? If so, you can buy some antimicrobial hand cream -- it comes in a convenient, travel-size tube. And scientists at the University of California at Berkeley are working on a smallpox-and-anthrax detector no bigger than the tip of a ballpoint pen. They expect to have it on the market in several years.

By making these gadgets fun -- the kind of stuff James Bond might covet -- the homeland-security industry almost makes you forget that they're meant to be used only in horrible situations, like a bioterrorism attack. The industry has also been careful to make its devices discreet. Walking around with more high-tech equipment than Maxwell Smart could get you some pretty weird looks.

It's unclear how useful many of these new products would actually be during a terrorist attack. The Web site Safer America, for example, offers the Response Escape Hood, which, it claims, filters out ''chemical agents, biological agents and nuclear particles'' for a much longer period than ordinary gas masks. But how long is long enough? Let's hope that the people who buy them never have to find out.