If you like 'em have a look at the first two flickr shots.
http://www.flickr.com/photos/49353569@N00/
The one on the OT Soubitez taillight is reminiscent of the ones used on some
technical trials bikes.
You could change the bulb without using tools. These were hand fashioned by
the constructeur.
The set on the modern dyno hub add a classic touch to a KOF bike.
When I ride this bike and look down at these I get a little nostalgic.