Butler- Sweeper Tool

“No hostiles. Seems to be self-propelled.”
The trolley lurched over the steps.
“I don’t know who’s driving this thing, but he could do with a few
lessons.”
Butler bent low to the ground, scanning the trolley’s underside.
“No explosive devices visible.”
He extracted a Sweeper from his pocket, extending the telescopic
aerial.
“No bugs either. Nothing detectable at any rate. But what do we have
here?”
“ h-oh,” said Foaly.
“It’s a camera.”
Butler reached in, pulling the fish-eye lens out by the cable.
“Nighty-night, gentlemen.”

- Artemis Fowl, Chapter 9