I live in MN with those nasty troopers and My $90 Whistler from Best Buy works great,I have had 3 of them over the past 7 years and they have all been great at avoiding tickets. Though I dont rely on it, its just there to keep me in check when the super troopers are at it. I could have avoided a $300 ticket back when I was 18 if I would have had one, not knowing there was a trooper following behind me a mile back.