I will start over again. I forgot about the light. It was at the first power setting for at least 3 1/2 hours. Sometime after that the tail switch was flashing red. I eventually checked the light output and noticed that the light was much dimmer. I clicked the switch and the light went out and would not start again so I unscrewed the tail cap, screwed it back in and when I clicked it it it lit at the lower output. I will try again.

Thanks, I have to find a split ring.