laser is not really useless. you hope to catch the signal as it spread at a distance from the source, and or catch stray/deflected signals as they bounce off of other cars being "shot at". I do not remember the exact numbers but i think that over a quarter or half mile the lazer which starts very small becomes a very large signal. My failing mamemory wants to say over 30+ inches. i had the laser go off today and though "the man" was after me and got the car right in front of me, whewwwww. BTW many owners have multiple units i actually have two one in my everyday car(Yukon) and another that stays in the Viper or goes w/ wifey if she is going on a road trip.