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 |
Specifications
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) | 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: 50˚
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)
Weight
NU21 Headlamp Total: 1.54 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
Included
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
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.