I know I know. I think it is adjustable in the brightness. I thought I read 10 different settings. I already have Cygolites front and rear. just looking for some more light. I found a small battery pack on amazon yesterday. I am not sure I will like the separate battery pack but I like the almost 360 degrees of light. makes me more visible. I think. it will be interesting to test it out in my riding environment. EVENTUALLY.