Trail Runner 4 is the fourth generation of our original running headlamp. Itâ€™s got an improved light output of 350 lm, while keeping its original low weight and generous burn time. Itâ€™s got a light beam optimized for running and comes with a wide, anti-slip headband â€“ and since it runs on AAA batteries, you never have to spend time charging it. The battery pack can be carried comfortably on the headband or, thanks to the extension cord, it can be kept warm in your pocket to save battery life. So with the darkness out of the way, letâ€™s get to the running.