First light on the list requires 6 AAs. Looks like 2 wide, 3 deep- good luck mounting that anywhere on the helmet or bars.

For the record, my first front light I bought when I started commuting years ago was a Coleman Maxx RWB rated at like 115 lumens. Aside from the fact I discovered quickly it did not suit my needs at that time, I just had to toss it in the trash this past week- my kids were playing with it and broke the light head off trying to change the colors.