The Rhythm Gemini Illuminated Wall Clock is a battery powered illuminated wall clock with an illuminated dial that is activated when the light level is dark the room it is placed. White frame and glass crystal. A light sensor activates the illumination. No AC power required as this clock is completely battery operated. Four AA batteries will only need changing about once per year for this backlit wall clock. Continuous, Quiet-Sweep second hand eliminates any ticking sound. This is one easy to read illuminated wall clock.