... step-down circuit input about 2-3Ah.Theoretical luminance: 2000Lm for 1 hour;Dimming function: 100%-80%-50%-30%-10%-Strobe ... ;Circuit function: low-voltage protection and high efficiency DC-DC, circuit will cut down power automatic when voltage of battery is low ... , water project, forestry, outdoor, explore, trip and so on. Supply High Power Rechargeable Portable LED Flashlight 2000Lm 30W