At a Glance#
Product : Nitecore NU25 UL
Brand : Nitecore
Best For : Ultralight hikers and trail runners who want a dual-beam headlamp that barely registers in the pack
Form Factor : Ultralight dual-beam headlamp with elastic cord headband
Buy Now : View on Amazon
Key Highlights:
- 400-lumen max output on Mix mode, reaching 64 metres at 1,029 candela
- Separate spotlight and floodlight emitters, usable alone or mixed together
- Red light in constant-on and slow-flashing modes, plus SOS and beacon
- Built-in 650mAh Li-ion battery charged over USB-C, up to 45 hours at the lowest level
- IP66 rated and impact resistant to 1 metre
Who Should Buy This#
The Nitecore NU25 UL is the dual-beam version of Nitecore's ultralight headlamp line: a spotlight for distance, a floodlight for the ground in front of you, and the option to run both. It delivers 400 lumens and a 64-metre throw in a body small enough that you stop noticing it, which is the whole argument for a lamp like this.
Perfect for:
- Ultralight backpackers who count every gram and want a headlamp that barely registers on the scale
- Trail runners who need a floodlight for footing and a spotlight for reading the trail ahead
- Thru-hikers who want a 45-hour low mode and USB-C charging from a power bank on the trail
- Casual campers and dog walkers who want a pocketable headlamp they'll actually carry every time
Design & Build Quality#
The NU25 UL strips headlamp design down to the essentials: a compact housing made from durable PC material, clipped into a minimalist bracket-and-headband system, with the battery sealed inside rather than in a separate pack at the back of your head.
The elastic cord headband replaces the bulky nylon straps found on traditional headlamps. It stretches over beanies, helmets, or bare heads. Two buttons sit on top for one-handed operation. In the box you get the headlamp with its headband, a USB-A to USB-C charging cable, and the printed NU25 UL manual — no case or pouch, so it goes straight in a pocket.
Key Features#
Dual Beam: Spotlight, Floodlight, or Both#
This is the feature the model name is built around. The NU25 UL carries two separate white emitters — a spotlight for throw and a floodlight for spread — and lets you run either alone or mixed.
Nitecore's own FL1 figures make the trade-off concrete. Mix mode is the bright setting: 400 lumens on HIGH, 64 metres, 1,029 candela, for 2 hours 40 minutes. Spotlight alone on MID puts 200 lumens down the trail at 58 metres and 862 candela — nearly the reach of full Mix at half the output, because all the light is going one place. Floodlight MID is also 200 lumens but only 23 metres and 138 candela, which is exactly what you want for your own feet rather than the horizon.
In practice you run flood for camp chores and footing, spot when you need to identify something at distance, and mix when you want both and do not care about runtime.
400 Lumens, 64 Metres, 1,029 Candela#
The headline numbers belong to Mix HIGH: 400 lumens, a maximum beam distance of 64 metres and a peak intensity of 1,029 candela, measured to the ANSI/NEMA FL1 standard.
Read those together rather than separately. 400 lumens is how much light leaves the lamp; 1,029 candela is how concentrated it is; 64 metres is the distance at which the beam is still useful. A lamp this size is not going to light a valley, but it will comfortably cover a trail corridor and a campsite.
Runtime From 2h40 to 45 Hours#
Nitecore publishes a runtime for every level, and the spread is enormous. Mix HIGH lasts 2 hours 40 minutes. Mix LOW at 60 lumens runs 10 hours 25 minutes. Floodlight ULTRALOW at 6 lumens runs 45 hours — the max-runtime figure, and genuinely enough for a multi-day trip if you are disciplined about which level you use.
That is the honest way to read any headlamp spec sheet: the 45-hour number and the 400-lumen number never happen at the same time.
Red Light, SOS and Beacon#
A dedicated red LED offers two modes — constant-on at 10 lumens for 16 hours, and slow flashing at the same 10 lumens. Red light preserves adapted night vision and won't blind your tent mate at 2 AM.
Beyond that there are two emergency modes, SOS and beacon, both at the full 400 lumens.
USB-C Charging#
The built-in 650mAh lithium-ion battery charges via USB-C through an intelligent charging circuit. The supplied cable is USB-A to USB-C, which is the right way round for topping up from an older power bank or a laptop port.
The battery is sealed in, so there is no swapping a fresh cell at a trailhead — a power bank is your only way to extend a long trip.
Technical Specifications#
Max Output : 400 lumens (Mix HIGH, 2h40min)
Max Beam Distance : 64 metres
Max Beam Intensity : 1,029 candela
Beam Configuration : Dual beam — spotlight and floodlight, usable separately or mixed
White Levels : Mix HIGH/MID/LOW, Spotlight MID/LOW, Floodlight MID/LOW/ULTRALOW
Red Light : Constant-on 10 lumens (16h) and slow flashing 10 lumens
Special Modes : SOS and Beacon, both 400 lumens
Battery : Built-in 3.7V 650mAh Li-ion, USB-C rechargeable
Max Runtime : 45 hours (Floodlight ULTRALOW, 6 lumens)
Waterproof Rating : IP66 (dust-tight, resistant to powerful water jets)
Impact Resistance : 1 metre
In the Box : Headlamp with bracket and headband, USB-A to USB-C charging cable, printed manual
Pros & Cons#
Pros:
- Two separate emitters give a real spotlight and a real floodlight, plus a mixed mode
- 400 lumens, 64 metres and 1,029 candela from a lamp this small
- Spotlight MID reaches 58 metres on half the output, so distance costs little runtime
- 45-hour maximum runtime on the floodlight ultralow level
- Red light in both constant and flashing modes, plus SOS and beacon
- USB-C charging with a USB-A ended cable that works with older power banks
- IP66 dust-tight and jet-resistant, plus 1-metre impact resistance
Cons:
- 650mAh battery is small, so the bright levels drain it quickly — 2h40 at full Mix
- Battery is built-in and not user-replaceable in the field
- Elastic headband may feel less secure than traditional nylon straps for some users
- No case or pouch in the box, just the lamp, cable and manual
- Nitecore does not publish a weight or dimensions for this model, so pack-weight planners have nothing to work with
Final Verdict#
Buy it. The Nitecore NU25 UL gets the important thing right for a small headlamp: it does not make you choose between throw and spread. 400 lumens and 64 metres on Mix, a floodlight for your feet, a 45-hour low mode and USB-C charging, all in something you forget you are carrying.
Our recommendation: Buy it for the dual beam, not for the headline lumens. If you want switchable colour temperatures instead, that is a different lamp — Nitecore's NU25 MCT UL — and it has its own spec sheet. View on Amazon