Nitecore® NU21 USB-C Rechargeable Headlamp

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  • Dual Beam White – Full Field Mix
  • Brightness up to 360 lumens, runtime up to 37 hours
  • 4 brightness levels + 2 rescue modes
  • Red light preserves night vision
  • Integrated Li-ion USB-C rechargeable battery
  • Plug into power bank to recharge
  • Lightweight  1.54 oz (43.7 g)


Nitecore® NU21 is an ultralight USB-C rechargeable headlamp with a more straight-forward, simple mode menu than the full-featured NU25-UL. This dual beam headlamp has four brightness levels up to 360 lumens, a runtime of up to 37 hours on Ultralow, a red light to preserve night vision, plus two rescue modes. The battery is a little smaller than NU25-UL, 500 mAh vs. 650 mAH. The standard dual shock cord UL headband is comfortable and highly adjustable to fit your head, hat, or helmet. And recharge by simply plugging into a power bank.

NU21 uses unibody TIR optics to mix two sources for a fully illuminated field - one with wide-angle flood illumination for outstanding night vision and another with more focused spot illumination for longer distance vision. Unlike NU25-UL, the two sources can only be operated together and not independently. For reading or close-up work, the light tilts down up to 50˚. There’s also a red light to help preserve night vision that won’t blind your friends. Use during star gazing, map reading, night photography, gear organizing, or doing camp chores. Use Slow Flash for a repeated short red flash to indicate caution. 




The headlamp has two buttons – POWER and MODE. Double press POWER to direct access Ultralow. Or long press POWER once for Low in Mix mode. Repeatedly press POWER to cycle from Low>Mid>High>Low. Short press MODE to switch modes. Repeatedly press MODE to cycle from White>Red>White. Long press either button to turn off.



For direct access to Red, long press MODE for Low, then repeatedly press POWER to cycle from Low>Short Flash>Low. Long press either button to turn off.

You can also access two rescue modes, SOS and Beacon. SOS repeatedly flashes SOS in Morse code (. . . ––– . . .), while Beacon repeatedly flashes a single short flash. Double press MODE to enter SOS mode. Repeatedly press POWER to cycle from SOS>Beacon>SOS. Double press MODE again to return to the previous state.

Long press both buttons at the same time to lockout and prevent the light from turning on while in your pocket or pack. The headlamp flashes three times to indicate lockout. Long press both buttons again to reactivate the headlamp and enter Ultralow mode.





NU21 has a built-in 500 mAh Li-ion rechargeable battery that’s much more sustainable than AAA batteries. An intelligent protective charging circuit and a USB-C connection make it quick and easy to recharge. There’s no need to worry about running out of power or replacing batteries, just plug into a power bank, wall charger, computer, or car (USB cable provided). The light maintains full functionality while charging.

To see how much battery power is left, with the light turned off, short press MODE and blue power indicators will light up. One light equals 25% left, 2 lights 50%, 3 lights 75%, and 4 lights 100%. Plug it in and the four blue lights will flash. When charging is complete, the four blue lights will become steady on. It takes approximately 1.5 h to fully charge the battery. A rubber cover protects the USB-C port from dirt and moisture.


Compare Headlamps

Compare Nitecore NU21 Nitecore NU25-UL
   White Mix  
   White Spotlight Only    
   White Floodlight Only    
   White Ultralow 6 lumens/37 h 6 lumens/45 h
   White Low 60 lumens/8 h 60 lumens/10.4 h
   White Mid 160 lumens/3.5 h 200 lumens/4.7 h
   White High 360 lumens/2 h 400 lumens/2.7 h
   Red Low 5 lumens/26 h 10 lumens/16 h
   Battery 500 mAh 650 mAh




LED Mode Output (lumens) Runtime (hours/min) Beam Distance ft (m) Beam Intensity (cd)

  White - Spot + Flood Mix

Ultralow 6 37 h 20 (6) 10 
Low 60 8 h 79 (24) 150 
Mid 170 3.5 h 128 (39) 399 
High 360 2 h 190 (58) 840 
SOS 360      
Beacon 360      
  Red Low 5 26 h 15 (4.5)
Slow Flash 10      


LED Color Temperature: 5500K, Neutral White

Battery: Built-in rechargeable Li-ion, 500 mAh

Lighting Modes

     White: Ultralow/Low/Mid/High/SOS/Beacon

     Red: Low/Slow Flash

Beam Pattern

     Floodlight: 100˚ wide-angle    

Body: Polycarbonate, impact resistant

Angle Adjustment: 5

Switch: Top Power and Mode buttons, rubber

Charging Connection: USB-C, side, rubber cover (USB-A to USB-C cable provided)

Charging Time: 1.5 h

Dimensions, Light with Bracket (LxWxH)

     NU21 Headlamp: 2.37 x 1.3 x 1 in. (60.1 x 33 x 25.5 mm)    

USB Cable Length: 20 in. (0.5 m)


     NU21 Headlamp Total1.54 oz (43.7 g) measured, 1.55 oz (44 g) specified

     USB Cable: 0.5 oz (14.3 g)

Impact Resistance: 3.3 ft (1 m)

Ingress Protection Rating: IP66, complete dust protection and high-pressure water jet resistant


     1x Rechargeable headlamp with UL headband

     1x USB-A to USB-C charging cable, 20 in. (0.5 m) long     


User Manual

Nitecore NU21 Headlamp User Manual



  • Very bright light, to avoid eye injuries, DO NOT stare directly into the light and DO NOT shine the light directly into the eyes of others.
  • Keep away from children to avoid injury.
  • DO NOT use if battery is damaged to avoid fire or explosion.
  • Charge in or on a fire-proof surface to avoid possible injury. DO NOT charge unattended.
  • Charge only at temperatures between 32-113°F (0-45°C) to avoid permanent damage and possible fire or explosion during charging.
  • Recycle or dispose of properly according to local regulations at end of life, DO NOT dispose in fire or incinerator as battery may catch fire and explode.

In no event shall Litesmith, LLC be liable for any direct, indirect, punitive, incidental, or special consequential damages, to property or life, whatsoever arising out of or connected with the use or misuse of its products.

2 Reviews Hide Reviews Show Reviews

  • 4
    2nd Generation NU21 with UL Band

    Posted by Tim Brown on 14th May 2024

    This is a fantastic headlamp. It majors in the majors with just the right combination of light modes for making its use easy and simple. The UCB-C charging configuration and cover on the side of the lamp makes charging a breeze. The lamp rests comfortably on your forehead and the swivel is efficient and easy to adjust. The Nitecore UL headband, though, not so much. The thick shock cord, the double cord for the headband configuration, and humongous toddle makes for uncomfortable wear. I switched it out for the DIY version of first generation Litesmith UL headband and am now a happy camper! My only suggestion is Litesmith offer a purchase option with their UL headband.

  • 5
    Great headlamp

    Posted by Cassandra on 8th Oct 2023

    Bright, easy to use with minimal learning curve with buttons. Comfortable, has a little foam pad on the bracket so sweat doesn't make it feel slick. Swapped out the band for some thinner shock cord (also purchased here) to save a couple more grams. Nice that it's USB rechargeable. Only wish it tilted downward to a full 90° so I'm less likely to blind my campmates lol, not a huge deal though. Happy with this purchase.