U.S. Customs and Border Protection has stationed a mobile Radiation Portal Monitor in Friday Harbor, a port of entry into the United States.

The truck-mounted RPM is a completely self-contained, passive monitoring device that screens for dangerous radiological devices or materials that might be smuggled into the U.S. in vehicles arriving aboard the international ferry.

“Radiation Portal Monitors are a great addition in our layered approach to securing the nation’s border while facilitating legitimate travelers and trade,” Port Director Barry Clement said in a press release. “They enable us to detect one of the greatest potential threats to our country without undue delay or hardship to the traveling public.”

Chief Thomas Schreiber said CBP employs mobile RPMs as part of its strategy to prevent terrorists and their weapons from entering the country. CBP has permanent RPMs located along the land border environment and in various seaports.

The mobile RPM enables this technology to be moved from port to port, making the screening process more efficient.