Olight T15 Q5-2008 Flashlight Uses one AA battery Five brightness Levels and Two SOS and Strobe Modes Remembers last setting when powered on and off Three Modes: Illumination, SOS (125 lm for 5hrs-25lm) and Strobe (120 lm/3.5 hrs) Five Levels of Constant Brightness:120 lm (0.8 hrs)-105 lm (2 hrs)-60 lm (5hrs)-25 lm(12hrs)-11 lm( 25 hrs)