I was driving on I-75 today with a cobra user in the car. She got it from her boyfriend about it a year ago and swears by it. I happen to have difficulty explaining things to her, so when she says things like "this is one of the best detectors out there, it costs like $180 new!!", I just kept my mouth shut. In any case, I got a week Ka alert on a straightaway, which slowly ramped up evenly until we saw the police cruiser on the shoulder running his rear antenna. The distance from first alert to the LEO ended up being just short of 2 miles. Naturally she wasn't so confident about her cobra after today.