The Einstein™ 1000 by NEBO is a low-profile, compact 1,000 lumen headlamp with 5 light modes featuring flex power. Use the included rechargeable battery or 2 x CR123A batteries.5 LIGHT MODESTurbo (1,000 lumens): 10 second intervals / 120 metersHigh (350 lumens): 3 hours / 55 metersMedium (150 lumens): 6 hours / 50 metersLow (10 lumens): 18 hours / 14 metersRed (5 lumens): 12 hours / 1 meters*Runtime is reduced by about 20% when using 2 x CR123A batteriesDESIGNCompact and lightweightDurable ABS and aluminium constructionWater resistant (IPX4)Turbo mode includedFlex PowerOPERATIONTop-positioned buttons for power and mode selectionACCESSORIESLi-ion 18650 rechargeable batteryOne size fits all head strapUSB-C charging cableBATTERIESPowered by 1x Li-ion 2200mAh 3.7v or 2xCR123A batteriesSPECSWeight: 123 gramsDimensions (L) 12.7㎝ X (W) 5.08㎝ X (H) 7.62㎝The EINSTEIN 1000 FLEX Headlamp features Flex-Power, high-power 1000 lumen Turbo Mode, 4 additional light modes, Direct-to-Red and an adjustable head strap.LIGHT MODESMODES LUMENS HOURS METERSTURBO 1000 10 SEC 120HIGH 350 3 55MED 150 6 50LOW 10 18 14RED 5 12 1OPERATIONA top-positioned button controls the power and light modes.DIRECT TO REDWhile OFF, press and hold button to activate Direct-to-Red. The next button press (within 8 seconds) cycles through the light modes in reverse (RED • LOW • MEDIUM • HIGH • OFF). TURBO MODEWhile ON, press and hold button to activate TURBO MODE. After 10 seconds on TURBO, previous mode is resumed.CHARGINGUnscrew the battery cap cover. With the USB cable connected to power, plug the USB-C end into the positive ( + ) end of the battery. Charging indicator glows red when charging; green when fully charged. FLEX POWERAllows the headlamp to operate with the included rechargeable battery, or two CR123A non-rechargeable lithium batteries.ADJUSTABLE HEADSTRAPSimple, convenient adjustability for any size.