About this item Type: radar velocimeter Model: V7 [Relative speed sensing auto mute system virtually eliminates false alarms] --- Relative velocity sensing auto-off feature will make your detector undetectable by currently available radar detectors, . A memory function that electronically remembers radar detector settings indefinitely, even in the event of a power failure. [Caution & Customer Service] --- This is a simple radar signal band detector, there is a radar signal on the road will ring, if there is no radar signal, it will not have any response, suitable for old drivers familiar with the road conditions. Traffic light photography and other pressure line type of fixed points without radar wave speed measurement, NOT in the scope of work of this product, please know.