This handy upgrade for the mag light not only gives you light at the push of a button but also gives you the option of light strength. There are 5 light modes: 100%, 50%, 25% power, slow, and fast strobe. There are also 3 power levels that help to extend battery life to make it last lasts four times longer! Auto-off(14.5 minutes) in the first 3 modes prevents accidental drainage of battery. At 13 minutes the light will flash to signal that it is close to shutting off and prompt you to hit the button to re-activate for another 14.5 minutes. At 13.5 minutes the light will flash to signal that it is close to shutting off and prompt you to hit the button to re-activate for another 14.5 minutes. At 14 minutes the light will flash again to signal that it is close to shutting off and prompt you to hit the button to re-activate for another 14.5 minutes. At 14.5 minutes the light will turn off unless it has been re-activated. This upgrade also helps you find-in-the-dark by flashing evey few seconds. This incredible upgrade is quick and easy to install.