Great. carry extra batteries
Two brightness settings on the LEDs and a separate high-power incandescent - very useful. I use the "tactical" version of this thing with red LED's; smaller signature and allows your eyes to remain adjusted to low light. The top strap is not really needed and can be removed. The headlamp and stays put running. You will need to use something metal to open the battery housing as the recommended method works poorly. (A dog tag works great.) Also carry extra Lithium 123's if you will be out a while. Sure Fire makes a great spare battery carrier.