From Jim Spellman CNN Washington bureau WASHINGTON (CNN) -- Though it looks like a space-aged android playing the harmonica, it's actually a device designed to protect you in a biological or chemical attack. The so-called Oxygen Generating Mask creates its own oxygen from the carbon dioxide and moisture exhaled by the wearer. It promises 15 to 30 minutes of breathing time with no clunky oxygen tank, and it sells for about $200. The product was one of hundreds on display recently at a massive homeland security trade show where everything from mobile command centers, tiny surveillance cameras, robots and a soldier's helmet equipped with a video camera were on display. Companies ranged from industry giants like Northrop Grumman to smaller ones like Oxy 911, the South Korean company that designed the oxygen mask. Govsec 2008 provides a chance for companies to pitch their wares in an effort to secure some of the millions of dollars in government contracts. "People come to the show to look at what types of products meet not only their homeland security goals, but all their security needs," says Kristina Tanasichuk, the director of Govsec, short for the Government Security Conference and Exposition. Thousands of police, firefighters, homeland security experts and military officials weaved their way between 450 vendor booths.An estimated 7,000 shoppers were expected to attend the expo, which became an annual event starting in 2002, after the terrorist attacks of September 11, 2001. Watch security for sale » Homeland Security Research, a Washington-based consulting firm, estimates that the homeland security sector in the United States is a $30 billion a year industry and expects the sector to grow to $35 billion by 2011. The leading segments of the market include electronic hardware, cyber security, border protection and airport security, according to the firm. Hundreds of millions of those dollars flow from the Department of Homeland Security to states and local government through a variety grant programs. The local leaders then have to use the money on approved products and services. "There are lots of funds going from DHS to the locals," Tanasichuk says. Govsec helps cops, firefighters and others trying to navigate the maze of federal programs by showing them "where the money is coming from, how to apply for those grants and how to figure out what kind of priorities homeland security will have for the next year," Tanasichuk says. That's not always a good thing, say critics who charge that DHS is becoming a vacuum for wasteful bureaucratic spending on a host of new technology. "I call it boys with toys syndrome," says James Carafano with the conservative Heritage Foundation. He believes the grant programs are wasteful and haven't yielded results, other than encouraging local law enforcement and other security personnel to buy expensive, fancy gear. "It's not only wasting money. It's actually making us unsafe by focusing on things we don't need," Carafano says. In the 9/11 Commission's report issued in 2004, the panel warned of just that, saying "homeland security assistance should be based strictly on an assessment of risks and vulnerabilities." "Federal homeland security assistance should not remain a program for general revenue sharing," the commission said. "Congress should not use this money as a pork barrel." DHS defends its spending. It says it has spent $22.7 billion in federal grants to "states, territories, urban areas and transportation authorities" to enhance their security apparatus. Another $3 billion is slated for 2008, according to DHS. Back at the expo, E-One, a Florida company, touts what it calls the first hybrid mobile command center, with an array of electronics run on a hybrid generator requiring a fraction of the fuel of a conventional vehicle. "We ran communication with police and fire out of this truck at the Super Bowl," says E-One's John Doperalski. "We filled this truck up after 7 days ... and only put 20 gallons of fuel in it." Nearby, Northrop Grumman displayed its Andros HD-1 robot. It can climb stairs and go into dangerous situations to defuse bombs, controlled via a video-equipped remote station. Jim Daniels, the robot handler, predicts it won't be long before homeland security technology filters down to the general public. He predicts that robots will be in tens of thousands of American homes within a decade. "Robots -- really they are the future and I think they are going to be a big boom in technology," he said, adding, "I can't wait."