On highest setting, the light is bright and lasts for about two hours. Set at the lowest setting, it is the equivalent of a night-light, enough to find your way through a dark room, and lasted an incredible 170 hours in my test. One continuous week! The setting is continuously variable, and set to the approximate mid-range setting, it was reasonably bright and lasted a little over five hours. I will find these very useful for emergency lighting during power outages, and occasional use for patio lighting.