My $15 (shipped) HW radar gun has been surprisingly accurate. My test car # 7 Teegray was clocked at between 377 and 435 scale MPH on the backstretch in five runs. On the midway straight all runs were above 400 with one at 525. The home stretch speeds are around 300. This method of qualifying cars for my races beats having to set up the 6 foot drag strip and qualifying the cars according to the distance traveled across my sketchy concrete floor.