When your entire business consists of selling fruit drinks ("smoothies"), I suppose you're always looking for something to differentiate the business.

Smoothie King apparently thinks its new RFID-enabled spending cards may be one such differentiator -- and a sales generator.

The spending cards are actually key chain fobs. Increasingly, consumers are paying for their smoothies with these RFID key fobs.

Smoothie King implemented the pilot program in April of 2006, after research showed that consumers tend to spend more with prepaid cards, than they do with credit cards or cash -- up to 25% more. The company wanted a quick transaction solution so they went with the RFID key fob. The payment infrastructure was provided by First Data.

Download the Smoothie King RFID Case Study here.

It's all part of a larger trend toward contactless payment systems.