No cumbersome cords. Choice of 3 simulated lighting conditions: daylight, incandescent and ambient light. Pays for itself with the price of one remake. On/off button does not need to be held down. Reduces glare and reflective highlights. Easily toggle between 3 lighting conditions with one-touch control. Provides consistent lighting conditions between dental office and dental laboratory for shade analysis. Eliminates shadowing from upper lip and distracting outside color sources from interfering with shade selection. Eliminates color distraction in the oral cavity. 2 - AA batteries. L.E.D. provides 30,000 hours of life. Constant Light Output.