The U.S. Border Patrol is using small robots to search drug tunnels along the country’s southern border.

The Border Patrol bought three of the robots, which are about 1 foot tall and weigh 12 pounds. They cost $40,000 each and were paid for with money and property seized in drug raids.

Many of the underground tunnels are unstable, so the robots eliminate some danger for border agents. The robots have wireless cameras, and agents can operate them remotely in a fraction of the time that it would take a human to search tunnels.

Hear Trace Gallagher’s full report above.