Specification: Material:Aluminum alloy. Low voltage warning: yes. Reverse polarity protection:yes. Lens Type:Ar-coated lens. Reflector:Smooth. Switch position: Side. Mode memory:Yes. Tail stand:Yes. Maximum charging current: 2A. Battery charger includes: Not included. Battery type required:1*21700 battery (not included). Number of batteries required:1 . Size: Head/body/tail diameter; 40mm/27.5mm/29.5mm. length:143.8mm. Product weight:145g. Features: 1.click the button  ->  flashlight is turned on with last brightness -> press the button,brightness ramping up -> release and press the button again,brightness ramping down. 2.flashlight off, press the button  ->  moonlight mode  (0.2%)   [This brightness will not be remembered]. 3.flashlight on or off, 2-click the button  ->  turbo 100%. 4.flashlight off,3-click the button   ->  strobe. 5.flashlight off,4-click the button   ->  tactical mode, only 100% ,4-click the button again to quit tactical mode. 6.flashlight off,5-click the button   ->  voltage detection . 7.flashlight off,6-click the button   ->  normal ramping mode switch to 4modes 1%-10%-40%-100%. 8.flashlight off,10-click the button   ->  Lock mode,The flashlight will flash once under any operation, which means the flashlight is locked.10-click the button again to quit lock mode,Please note that this is the only way to unlock. Package included: 1 x M21F KW CULPM1.TG/SFT40 Powerful 21700 Flashlight (battery not included)a