A few years back I had a whistler pro 78 and it would alert to the mobile speed vans around town. I moved away and purchased a Bel RX65 and ran it in USA mode, then I moved back and the RX65 did not alert to the vans. Then I had a bfo and changed the RX to international mode and it alerted every time, the Ka radar in the van was waaay out of tune. Now I am wondering how many times did I drive past a cop with no alert thinking they were not running radar when their gun was just out of tune. Anyway I just purchased a new X50 Black it is a little better on k and noticeably better on Ka plus I like the angled display and the ability to have the display completely dark.