Dr.Plex's @EEZ (TM) Light
Plex Lights light up your ships by emitting a colored or white glow that illuminates surrounding blocks. Plex Beacons are different in that they do emit light but also a 'beacon'-like glare that can be seen from quite far away.
Colored lights can be used for decoration, illumination and color-coding of areas or objects. You might also agree to illuminate your factions' ships and stations with a certain color for easy recognition.