The wall mounted clock projects the hour and minutes hands to the wall with a 68 cm (~27 inches) diameter. The built-in illumination is enough even for daytime use.There are two power sourcesin the clock, one for the clock, the other is for the illumination. The clock works with one AA (double A) size battery(which lasts around 4-5 months or more.) and the light is powered upwithatransformerwhich is supplied with the clock.The clock uses12 V - 10 Watt 1.2 MA halogen G4 bulb.All you need is to insert AA size battery (there is 1 battery in package) to make the clock run and connect the supplied transformer to the mains to light it up.If you have any question feel free to send me email andread my feedback please....!We have a large number of clocks.!UNIQUE GIFT ..FOR YOU OR YOUR FRIENDS..Please don't wait purchasing until last minute ..