After 9/11, lawmakers looked for new rules and tools to help increase security.  Anyone who has flown is familiar with the "3-1-1" rule governing liquids.  but some complain that the tools, at times, are too invasive.

FOX News Radio's Jessica Rosenthal reports on what some of those tools are used for in Part 23 of our month-long special series, "9/11: 10 Years Later":

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In our next report, former Defense Secretary Donald Rumsfeld reflects on the attack on the Pentagon and the American response to 9/11.

CLICK HERE to listen to Parts 1-22 of our month-long special series, "9/11: 10 Years Later"