THESE ARE GREAT!  Before these came along I used to drill a tiny hole through the little molded plastic fake lamps that come with many structure kits.  Then tried to put a tiny 1 mm lamp and wire through it.  WOW!  What a workout that was.  But now, it's all done for you.  These HO scale gooseneck lamps come with a very tiny led already assembled in them!  They use 3 Volts and 15 to 20 milliamps.  If you will let me know what voltage you'll be using I'll include the proper resistor.  Otherwise I'll include one for 12 Volts.  Since these are leds they won't even get warm, so they don't have any of the plastic damaging heat caused by a 12 volt lamp! If you'd like to get more than three, there will be no additional shipping charge!