GBU-28 "Bunker-buster" bomb

DESCRIPTION: This is a 5,000-pound laser-guided bomb that can be dropped by an F-15E. It's designed to penetrate 100 feet of earth and 22 feet of reinforced concrete.

ANYTHING NEW? This bomb originally was jury-rigged from an 8-inch-wide howitzer barrel.

After a hasty development, two GBU-28s were rushed to the Gulf and dropped from U.S. Air Force F-111s. New versions have refinements that make them more accurate. Sources say the B-2 bombers at Whiteman Air Force Base have the capability of dropping these "bunker-busting" bombs.