4-5 D cells run approx 11 hours at 260 lumens <img src="/ubbthreads/images/graemlins/thumbup.gif" alt="" />. Even after batteries are older you are still getting 200 lumens for a few more hours. Kicks [censored] on other lights <img src="/ubbthreads/images/graemlins/thumbup.gif" alt="" />. The only problem is when they are availible from Gene they go FAST !! <img src="/ubbthreads/images/graemlins/crazy.gif" alt="" />