The DFR3 detects emissions from Radar Guns and sounds an audio alert for the driver. The detector determines which band range the signal is from and displays that Frequency type on the display (x, K, KA, or L). the Frequency strength (1 through 5) also displays as applicable. If there is a specific alert code, that is also displayed. The DFR3 utilizes two different modes for highway or City use.