This UltraFire WF-900L CREE MCU emitter flashlight is a Constant current 3-mode (High/Low/Strobe) with memory powered by two pieces 18650 or 2 pieces 18500 (by removing the 30mm body extention) with output measured at continuous 400+ Lumen in High. It is well built and well balanced. Using high capacity 2400mAh batteries, this light will run for about 70 minutes on High.

NOTICE: Due to the high current and light output, this light will generate significant heat. This light will become hot to the touch after 20 minutes of continuous use in high mode. This light has thermal protection in the driver board and will begin switching between Low and High modes once it gets hot. This light should not be operated for more than 20 minutes continuously in high mode.

Packed with the CREE MCU 4-die emitter, e-lectronics has measured the output of this flashlight at a constant 400+ lumen. Granted, most other vendors are advertising P7 flashlights as 900 lumen becuase the peak rating of the emitter is 900, e-lectronics tells it like it is. Don't be mistaken, this light is EXTREMELY BRIGHT. 

MODES: This P7 flashlight has 3 light modes with memory (High/ Low/ Strobe). Modes are switched by partially depressing the tail switch. This light does have memory and will retain the last used mode when powered off.

Light Output (Lumens): [High: ~400] [Low: 160] [Strobe: medium rate]

Battery Input Current:  [High: 1.8A] [Medimum: 550mA]

Specifications:

50mm AR Glass lens
Medium Orange Peel reflector
SSC P7 C-Bin SXO tint
Heat sink: through body
Driver: Constant current with thermal protection
Reverse Clicky tail switch
Anodized black finish
Powered by 2 x Li-ion 18650 / 18500
Weather and Shock resistant
Lenth w/o extender: 180mm / 7"
Lenght with extender: 220mm / 8.25"
Body Diameter: 30mm / 1.2"
Head Diameter: 55mm / 2"