The present invention provides a device, system, and method for detecting and measuring the bi-directional flow of a fluid through a fluid meter, such as a household or business water meter. In one device embodiment the invention comprises a logical switch collar (12) disposed over an analog fluid meter...http://www.google.com.au/patents/US6755148?utm_source=gb-gplus-sharePatent US6755148 - Dual magnetic register for a utility meter
