The letters X, K, and Ka designate radar frequency bands used by radar based speed monitors. The letters correspond to designations given by Federal Communication Comission (FCC) frequency bands reserved for speed monitor equipment.
- X band - 10.525 GHz
- K band - 24.150 GHz
- Ka band - 33.4 ... 36 GHz
The number (range is 1 ... 5) is the radar signal strength, where 1 indicates weakest signal (you are still at some distance, or maybe false alarm) while at 5 you should be able to see the white in the eye of the cop holding the radar gun.
The letter V indicates the detection of a "Detector Detector". Devices like the Cobra are illegal in some countries and police has counter-measures available to detect some radar detectors. The maker of the Cobra states, their products go unnoticed but that won't help you if highway patrol sees the thing sticking on your windshield.
The letter S indicates hazard warnings (like train crossings).
Finally, L indicates detection of a LASER based velocity detector.