It's tough to shake off a Bulldog. Shippers from Fortune 500 companies in the pharmaceutical, retail and high-tech industries found that out firsthand this summer during a series of pilot tests on Bulldog's MiniBoss covert security device.

During the trials, testers were challenged to conceal the devices in their cargo shipments to see if they could foil the MiniBosses' efforts to transmit signals tracking their whereabouts as the vehicles criss-crossed the United States. But their efforts were to no avail. The device passed with flying colors, according to Bulldog. "We confirmed that no matter where or how they install the device, we can successfully get a signal from the inside of a transportation vehicle," reports Richard Booth, the company's vice president.

A covert tracking device (it measures only 4 by 3 by 2 inches), the MiniBoss unit is designed to be discreetly placed inside a cargo shipment. Once activated, it logs a history file, which traces the cargo's routes. Should a load be stolen, the device provides the tracking data needed to locate the missing load instantly. Bulldog claims that the system is more reliable than GPS systems, which can be disabled by thieves.