Nitecore NU25 review: the 50g ultralight head torch you always have with you

Who it's for

The Nitecore NU25 is the ultralight pick in this head torch cluster. It exists to solve one problem: the best head torch is the one you actually have on you when the light goes, and a 50g torch is one you never leave behind.

That makes it a trail runner's and fastpacker's torch first. If you count grams, run later than you planned, or want a capable light that disappears into a vest pocket, this is the one to point at. It is not built to out-throw the rugged, high-output torches further up this cluster, and it does not try to be. It is built to be tiny, bright enough for real use, and always with you.

One point of order before the specs, because it matters for what you are buying. There have been several NU25s. The original was a Micro-USB torch with a high-CRI emitter. The version Nitecore currently sells is the NU25 MCT, a USB-C torch with a different LED set: three switchable colour temperatures instead of the old high-CRI LED. Everything below describes that current MCT model, so you are not reading specs from a torch you can no longer buy.

Specifications

Max output

400 lumens

Beam distance

132m (peak intensity 4,351cd)

Light sources

Dual white beams (spot + flood) across three colour temperatures: 3000K warm / 4500K neutral / 6500K cool, plus a red light

Battery

Built-in 700mAh Li-ion (non-removable)

Charging

USB-C, full charge in approx. 75 minutes

Max runtime

45 hours at the 6-lumen ultralow setting

Weight

50g with headband (47g for the MCT UL elastic-cord version)

Water and impact

IP66, 1m impact resistance

Dimensions

60 x 34.4 x 27.2mm

Ultralight for running

The number that defines this torch is 50g. That is the whole point of it.

For context, the Fenix HM65R V2 I rate as the performance pick in this cluster weighs 144g, and the comfort-first Silva Trail Runner Free 2 Ultra lamp weighs 61g. The NU25 undercuts both. On a running vest strap or a light headband it sits so light that you stop noticing it, which is exactly what you want when you are moving fast and the torch is insurance rather than the main event. Nitecore also sells an MCT UL version that swaps the headband for a minimal elastic cord and drops the weight to 47g.

Small does not mean feeble here. 400 lumens and a 132m throw is real capability for a torch this size: enough to pick a line on a trail, read the ground ahead on a descent, and light a path home when a run runs late. It will not reach like a 2200-lumen navigation torch, but for running pace on known ground it does not need to.

The LED story is the other reason it earns its place. The current MCT runs dual white beams, a tighter spotlight for reach and a wider floodlight for close ground, and lets you set the white across three colour temperatures. 6500K cool for maximum brightness, 4500K neutral, or 3000K warm, which throws less glare back at you in mist and is easier on the eyes for a map. There is also a front red mode, useful for checking a map or a phone without wrecking your night vision. The 6-lumen ultralow setting runs for up to 45 hours, so as a long-life backup light it is hard to kill.

Charging is over USB-C, full in around 75 minutes, so a quick top-up from a power bank or laptop before you head out is easy.

The honest cons

The trade-offs here are the trade-offs of ultralight, and they are worth being clear about before you buy.

The battery is built in and non-removable. It is a 700mAh Li-ion cell sealed into the body, so when it runs flat you plug in and wait, you do not swap in a fresh cell. On a multi-day trip that means carrying a power bank rather than spare batteries, and over years of use a built-in cell is the part that eventually limits the torch's life. This is the single biggest difference between the NU25 and the rugged torches in this cluster.

Cold makes that worse. Any Li-ion battery loses usable capacity in the cold, and because you cannot pull this one out to keep a warm spare in a pocket, a hard winter night eats into both runtime and the headline output. For UK autumn and shoulder-season running that is a minor concern. For sustained sub-zero use it is a real one.

Reach is modest by design. 400 lumens and 132m is strong for the size, but it is not a long-throw navigation beam for finding a marker across a black field or spotting a cliff edge at distance. If your nights involve serious off-path navigation near hazards, this is not the tool for that job.

And the protection rating is IP66, not IP68. IP66 means it is dust-tight and shrugs off heavy rain and jets of water, which covers any British night out. It is not rated for submersion the way the top torches here are. There is also no rear safety light on the body, so for road-adjacent visibility you would clip a separate rear flasher to your pack.

Why pick it, or not, over the premium torches

The choice in this cluster comes down to what you are optimising for.

If you want outright power, reach, cold-weather reliability and a battery you can swap, the Fenix HM65R V2 is the pick. It throws 2200 lumens to 230m, it is IP68, it is rated to hard cold, and crucially it runs a removable 18650 you can swap for a warm spare when the temperature drops, with a lithium backup behind it. It is also nearly three times the weight, and more torch than a runner needs. That is the deal: the Fenix is the tool for serious night navigation, the NU25 is the tool you barely feel.

If comfort on the head is your priority, the Silva Trail Runner Free 2 Ultra is the rear-balanced alternative, with a rear red safety light built into the battery case and the option of 3x AAA as a cold and out-of-power backup. It is a lovely thing to wear for longer sessions. But it is heavier than the NU25 and its battery bulk sits at the back rather than vanishing entirely.

The NU25 wins on exactly one axis, and it wins it decisively: weight you stop noticing. For a trail runner, a fastpacker counting every gram, or anyone who wants a legitimately capable torch that lives permanently in a pack, that one axis is often the one that matters most.

Verdict

The Nitecore NU25 is the ultralight pick in this cluster, and it does that job well. At 50g it delivers 400 lumens, a 132m throw, three colour temperatures and a red mode, over USB-C, in a torch small enough that you never have a reason to leave it at home. For trail runners, fastpackers and gram-counters, that combination is hard to beat.

Go in clear-eyed about the trade-offs. The built-in battery cannot be swapped, cold cuts into its runtime, the reach is modest, and it is IP66 rather than submersible. Those are the costs of the weight, not flaws in the execution. If you need a torch for serious off-path navigation or sustained deep cold, the cold-swappable Fenix HM65R V2 is the better tool, and if head comfort matters most, the Silva Trail Runner Free 2 Ultra is the nicer wear.

But if you want the torch you always have with you, the one that weighs nothing and is still bright enough for real use, the NU25 is exactly that.