iTP is arelatively newcomer to the high tech LED flashlight market, but don't think that means their products are not top notch!  This light is one of the best of the dozens I reviewed a prospective products.  You won't be dsappointed in this light. 

This light incorporates some very creative and innovative features.

• LED type:Cree 7090-XR-E Q5,life span up to 50000 hours 
• Battery reverse-polarity protection
• Made of aerospace grade aluminium alloy 
• Ergonomic design for various functions:anti-rolling,anti-shattering,water resistant,shockproof
• Hard finish with Type Ⅲ anodization
• Aluminium alloy reflector with half smooth and half orange peel
• Output level: 6 lumens---190 lumens
• Digital infinite beam adjustment function,choose and memorize the favorite brightness level
• Constant current output control system
• Runs on single CR123A battery,also compatible for 16340 battery (battery NOT included)
• Reverse switch, Illumination-Strobe-S.O.S function
• C9 length 90mm, Diameter 27mm, Weight 65g(excluding battery) 

      Here are some diagrams for runtime for your reference. 
   
       CR123A*1  battery
       Maximum output 190 lumens, for about 50 minutes (with brightness declines to 50%)
       Minimum output 6 lumens, for about 42 hours (with brightness declines to 50%)