The Quark RGB features a CREE MCE-RGB emitter. The MCE-RGB is a quad-die emitter that features a different color for each corner of the die: white, red, green, and blue!
The Quark RGB UI is unique. When the head is tightened, it is always white (or neutral white depending on your model). When the head is loosened, it is one of the RGB colors. Cycling between loose and tight will toggle through the three colors.The way to change modes is similar to the regular Quarks. Just tap the tail button to change modes (or just turn it on and off within 3-4 seconds). It will toggle between eight modes: moonlight -> low -> medium -> high -> max -> S.O.S -> strobe -> beacon.