Another important indicator, officials said, was Iraq's efforts to procure special aluminum tubes.

Still, American intelligence was never of a single mind on the question of aluminum tubes.

The high-tolerance aluminum tubes are only part of the story.

They have long focal ratios, and are constructed with a blue aluminum tube.

They have very long focal ratios and are sold in blue aluminum tubes.

The man held an aluminum tube a good seven feet long.

Gleaming, the aluminum tubes stood more than six feet tall, with three pipes coming out the top of each.

The fuselage structure was also built from 6061-T6 aluminum tube.

The B-5 was built around a cruciform frame of aluminum tube.

An administration official called discussions about the aluminum tubes and Iraq's intentions "a normal part of the intelligence process."