NEXTORCH K40 – Keychain Light with 300 lm Constant Light & 700 lm Strobe

17 grams · four light colors · USB-C
When you want more than just an emergency light on your keychain
In the dark parking lot, at the tent zipper, or when looking under the car seat, one thing counts above all: The light has to be there. The NEXTORCH K40 combines 300 lumens of white light with red, blue, and 405-nm UV light in a housing only 73 millimeters long.
Important before buying: The advertised 700 lumens are only available in strobe mode. The strongest constant white light delivers 300 lumens.
Honest assessment of the K40

Our honest assessment
The K40 is a versatile keychain and backup light, not a small searchlight alternative. Its biggest advantage is the combination of low weight, two separate control buttons, and multiple light sources
en. For short orientation, it works convincingly; for long work shifts, the built-in 180-mAh battery and IPX4 splash protection limit the use.
The measurement and operation test published by 1Lumen confirmed the 300-lumen high value after 30 seconds and largely the runtime specifications. At the same time, it showed the real disadvantages: The white light always starts on high, there is no electronic lockout, the light color appears cool, and the 405-nm UV LED is less suitable for demanding UV inspections than a specialized 365-nm lamp.

Fits well if …

you’re looking for a lamp that really comes along daily because it weighs 17 g;
10, 50, or 300 lumens are enough for close range and short orientation;
red light, conspicuous blinking light, and UV as additional functions are useful;
USB-C charging is more important than a replaceable battery.



Rather doesn’t fit if …

you expect 700 lumens as continuous work light;
the lamp must be waterproof for submersion;
you need low direct access, button lock, or mode memory;
you want to professionally inspect documents, minerals, or traces with UV.

What the functions mean in practice


300 lumens high Enough for a short path, a vehicle check, or orientation around the camp. The 78 meters is a standardized range value and not a guaranteed recognition distance.


10 lumens low The most sensible mode for keyholes, pockets, maps, or immediate close range. With up to 9 hours 15 minutes, it is the enduring level.


Red and red/blue Red light is suitable for discreet close-range illumination. Red-blue blinking is very noticeable but is not an official warning signal and should not be used misleadingly.


405-nm UV Can make fluorescence visible but does not replace professional authenticity, hygiene, or trace inspection. For many inspection tasks, a filtered 365-nm lamp is the better choice.

Operating note from the 1Lumen test
In the 1Lumen test, the front button starts the white light directly on high and cycles through high, medium, and low within three seconds. The second button calls up the strobe directly; long press leads to UV, then cycles through UV, red, and red/blue. There is no lockout or mode memory.
Practical consequence: Check the button position before putting it in a tight pocket. Nothing should press permanently against the switches on the keychain.

Trainer and user tips


Practice operation dry: distinguish white light and additional light button to avoid accidentally activating strobe or red/blue.

Use low level consciously: after starting on high, quickly switch to medium or low if glare and battery load are unnecessary.

Recharge before tours: the battery is fixed and small. For longer missions, plan an additional full-fledged lamp.

Close USB cover: IPX4 requires a properly closed charging port and only protects against splashing water.

Never evaluate UV result alone: visible fluorescence is an indication, not proof.

K40 or K30?


NEXTORCH K40 73 mm, 17 g, 300 lumens continuous light, multiple light colors, and integrated battery. The better choice if minimal size and additional functions are decisive.


NEXTORCH K30 142 mm, 850 lumens, IPX7, and optionally 10880 battery or two AAA. More sensible if stronger white light, replaceable power, and higher water resistance are more important.


Compare NEXTORCH K30 in the shop

Technical data with practical interpretation


White light 300 lm / approx. 1 h / 78 m 50 lm / approx. 1 h 30 min / 30 m 10 lm / approx. 9 h 15 min / 12 m


Special light 700-lumen white light strobe; red; blue; 405-nm UV; red/blue blinking. 700 lumens is not a continuous light mode.


Power Fixed
integrated 180-mAh battery, charging via USB-C. The battery is not designed for quick user replacement.


Protection IPX4 against splashing water and drop test from 1 meter. Not suitable for submersion and not classified as a rugged primary flashlight for heavy continuous use.


Dimensions and weight 73 × 16.5 × 16.5 mm; 17 g including fixed battery. The low weight is the key EDC advantage.


Material Transparent polycarbonate/plastic housing with aluminum head. The transparent body makes the electronics visible.


Manufacturer values under laboratory conditions; temperature, charge state, and aging can affect actual performance.

Scope of delivery

Clearly specified by the manufacturer: NEXTORCH K40 with fixed integrated 180-mAh battery and stainless steel clip. Please note the information on the specific original packaging delivered.

Safety, charging, and care

Do not shine directly into eyes; do not aim strobe at people from close range.
Do not direct UV light into eyes and do not use as the sole inspection method.
Do not use red/blue blinking light in a way that creates the impression of an official emergency signal.
Charge only at dry, undamaged USB-C port; close cover completely afterward.
Do not continue charging or use if deformed, unusually warm, or battery housing is damaged.
Clean lens and housing with a soft cloth; avoid aggressive solvents.

FAQ about the NEXTORCH K40
Does the K40 shine continuously at 700 lumens? No. 700 lumens are only specified for the strobe. The strongest constant white light is 300 lumens.
Does the K40 start on low? No. The 1-lumen operation and measurement test describes the white light starting on high. It then switches to medium and low within a few seconds.
Can I lock the buttons? The tested K40 operation sequence does not offer an electronic lockout. Therefore, the position on the keychain or in the pocket is important.
Is the flashlight waterproof? It is protected against splashing water according to IPX4. This is not equivalent to submersion protection according to IPX7 or IPX8.
Is the 180-mAh battery replaceable? No, it is fixed and charged via USB-C. For long missions, a second flashlight with replaceable power is advisable.
Is the UV light suitable for authenticity checks? Only as a guide. The K40 operates at 405 nm; an independent test showed weak results on certain banknote features. For professional inspections, a specifically filtered UV lamp is required.
What does the range of 78 meters mean? This is a standardized measurement for high. It does not mean that details can be reliably recognized at 78 meters under all conditions.

Tested ways to the right flashlight
Flashlights and lanterns for camp, EDC, and touring
Guide: Selecting NEXTORCH flashlights by use

Black Raptor
Honest advice. Sensible gear.
We come from training and application. That’s why we not only name the strong data but also small batteries, missing button locks, and real operational limits. This creates gear that fits your everyday life – and a community where experience counts more than brochure language.