Three C-Cell. 11 1/4" overall. Black aluminum housing. Up to 137 lumen output. Visible over 306m on high setting. Can be personalized for quick access to your preferred functions: full power, power save, strobe, SOS or Momentary On/Off. Uses three C-Cell batteries (not included). Runtime per battery set: 37 hours on high setting, 78 hours on low setting. Water resistant.