faiz, we use sound for tracking, on the advertisements, this is never mentioned...its the sound that tracks, tone changes when we have a target, gets higher as you approach, if you slow, the tone lowers in pitch, now if you would be able to jam, we would know it right away...its just a way to sell you something, trust me...I've seen them all...and also remember this, for us to be certified as operators, we must learn to quess, visually guess, or I should say as I would state in court, estimate your speed within 5 mph...I can write someone, at least here in IN, for excessive speed without radar, lidar, vascar...they are nice tools for knowing we are around, but not 100%...its just a big game for both sides, save your money, buy a cobra or something inexpensive, it will work just as well...although I know cheap versions, will give off more false signals....you be careful out there...