Laser Diffusers A laser gun fires a narrow beam of light in a straight line and records your speed in less than a third of second. Diffusers (or Jammers) combat this instant speed reading by firing their own laser or infra-red signal back to "confuse" the laser gun, which records an error message. Laser guns operators get error messages all the time so that, in itself, is perfectly routine and they often have to fire several times to get a speed reading. Your diffuser then continues to jam until it either switches off automatically or you switch it off manually. This is to allow the operator to fire again and this time record your speed. If this is done quickly enough then the operator assumes it's a normal error message and moves on to the next car, none the wiser. Ensure you switch it off every time, otherwise you will continue to jam and it will definitely arouse suspicion. It's safer to get one that switches off automatically after a short period of time.