Just to give you an idea of the battery life and power of these new lights, when racing 24 Hour Nationals in WI this past July I ran only the Double Shot Pro on my helmet with the larger Triple Shot Pro Li-Ion battery. I never had to switch batteries! Also, note that the new "Pro" lights have a high and low beam, and also a indicator light to show battery life. The Double Shot Pro battery is about the size of a pager or small flip phone. The Triple Shot Pro battery is twice that size.
Any questions?