You don't give much information. I am personally of the "brighter is better" group and usually that means just turning on the lights. However, I have a Z3 that uses 3-3 volt batteries. I am not sure if they make the particular model or not. That is not the issue. Generally, more batteries means more light until you get up in the really high $$ versions that allow less light and more time or more light and less time. The Z3 runs for about an hour, total time. With most of the high intensity lights, you don't want to run them for very long at a single time. I tend to do several short illuminations of 30 seconds to maybe a minute. The lights are great for looking for a person or a pet, but not searching for 20 minutes looking for a lost set of keys in high grass. In that case, the mag light is really a better option.