The amber side lights are really what I wanted. Hadn't purchased some already since they're typically on the expensive side. But when the full set was available for not much more than the side lights alone, I had to bite. I'm using the whole set. With the amount of light in Alaska mid-winter, I can't really have too many lights for my fatbike. In my opinion, amber side lights might be the most important in many cases. I can commute to work mostly on path & sidewalk. Most interface with traffic is crossing, hence visibility from the side is what you need.
This set went on our tandem. The amber lights are perfect to mounting mid-ship so cars and other riders can easily tell it�s a tandem.