heir simplicity, they generally cost less than a dollar. Readers (sometimes called interrogators) communicate with tags to retrieve and, sometimes, write information to the tag. Readers are designed to work with a specific type of tag in one of the four RFID frequency ranges: 125 to 134kHz, 13.553 to 13.567 MHz, 400 to 1 GHz, and 2.3 to 2.48 GHz. The reader also relays information into a database and other parts of an organi- zation's IT infrastructure. Despite its many variations, RFID is a fundamentally simple technology. What isn't SO simple, and what has contributed to RFID's slow progression into the mainstream, is its need to mesh with existing business systems and practices. Databases, networks, employee job duties-even warehouse layouts and production lines-must all be tweaked or entirely redesigned to accom- modate RFID. "It really changes many business processes throughout the organization," says Gartner's Woods. Yet RFID can also provide the rationale for a profitable business-line restructuring. Carlsberg-Tetley Brewing, for example, identified RFID as an opportunity to outsource the management of its beer kegs. "It will put the complexities and the rigor of content management into the hands of a better provider," says David Dixon, business solutions executive for the Northampton, England-based beer maker. Carlsberg-Tetley, one of the United Kingdom's largest brewers, recently sold more than 1 million of its containers (kegs) to Trenstar, a Denver-based SOMETHING IN THE AIR-RADIO AND LOCATION TECHNOLOGIES asset management company. Under this arrangement, the brewer pays for use of the containers on a "per fill" basis, whereas Trenstar retains legal posses- sion of them. In addition, Trenstar put RFID tags on each container and installed fixed readers alongside conveyors inside Carlsberg-Tetley's brew- eries. Delivery trucks are also equipped with readers that scan the kegs as before and after delivery. The arrangement is designed to allow Carlsberg-Tetley to improve its return on capital by removing t