I ordered 2 of these to run one on my head and one on the bars. The light and pack are very light and work comfortably on my head. I considered throwing the battery in my pack using the 36" extension but the extra weight is barely noticeable after a few rides. I use them on pretty tight but flat single track and there is plenty of light. On the roads a single light on the bars is plenty. Off road, a single on my helmet would be *enough* light but the second on the bars is definitely worth it. To be honest, I'd consider buying just this for the helmet and a brighter, but cheaper setup for the bars. Run time is great but I try to bounce back and forth between the hi/med/low to conserve battery. Mounting system was confusing at first but a quick youtube search helped me figure it out.