Output front 35 lumens rear 5 lumens dimensions front 25 x 25x 75 mm rear 25 x 25x 70 mm weight 56g run time front 64 hrs steadylow 100 hrs eco flash rear 7 hrs steady 200 hrs eco flash get started 1 pop open the light with a coin 2 take out the battery saver tab check your when you slide the battery back in 3 slide the unit back together firmly 4 press and hold the onoff switch for about 1 second to turn light on press