Model: UltraFire WF501B Cree R2 - Features a Cree XR-E R2-WC LED emitter - Powered by 1 x 18650 or 2 x 3.0V/3.6V CR123A batteries - Voltage input range: 3V~8.4V - 5-mode tailcap clicky switch with state memory: Hi > Mid > Lo > Strobe > SOS - Mode memory circuitry built-in -- returns the light to the previously used mode - 250 lumens maximum brightness (manufacturer rated) - 1000mA current output digitally regulated driver circuitry (manufacturer rated) - 40 to 60 minutes estimated runtime per charge (manufacturer rated) - Coated glass lens with aluminum textured/OP reflector