Review CYANSKY K3 v2.0 - 2000 lumens - 700 meters

Dec 3, 2012

was sent to me directly from CYANSKY for review.

For technical details: is external)
For purchase on Aliexpress: is external)

Established in 2017 in China, Cyanskylight Co., Ltd ( is external)) is an enterprise integrating R&D, production, marketing and sales. CYANSKY is focused on top-level LED flashlights, LED headlamps and accessories for hunting and shooting, tactical police law enforcement and self-defense, outdoor adventure, EDC etc.

I thank CYANSKY for giving me the opportunity to test the new CYANSKY P25 v2.0 and, object of this test, the CYANSKY K3v2.0.
With the K3 v2.0, CYANSKY renews the previous model bringing better performance with a maximum brightness now of 2000 lumens and a maximum peak beam intensity of 124.609cd.
CYANSKY K3 v2.0 is a medium size flashlight, 153.6mm long powered by a 5000mAh protected 21700 format battery with a maximum autonomy of 400 hours. On the K3 v2.0 we find the Luminus SFT-40-W LED which allows the K3 v2.0 to reach the remarkable beam distance of 700 meters.

K3 v2.0 has two switches, one on the tail and one on the side, four brightness levels and two special modes, Strobe and ECO mode, with IP68 waterproof and an operating temperature between -30°C and 50°C.
CYANSKY K3 v2.0 is particularly recommended for Military Forces, Security, Hunting, Search and Rescue etc.


Main features (by CYANSKY):

  • 1 * Luminus SFT-40-W with 50,000 hours of life
  • Powered by a 5000mAh 21700 Li-ion rechargeable battery
  • Tactical tail switch, one touch to light up
  • Side switch to change output modes
  • ECO/Strobe mode.
  • Maximum. 2000 lumens and 700 meters.
  • Max 400 hours of autonomy.
  • Working temperature: -30℃ to 50℃.
  • HAIII hard-anodized anti-abrasive processing surface
  • With battery power indication and low voltage warning function
  • Constant current output circuit to maintain constant brightness
  • Intelligent IC controls the temperature to avoid overheating and causing damage to the product or overheating of the surface causing discomfort
  • The case is made of A6061-T6 aircraft grade hard aluminum alloy
  • Tempered glass lens with coating on both sides
  • Anti-reverse connection design to prevent the battery from being installed upside down, causing damage to the circuit
  • Anti-roll and non-slip body design
  • With the use of the optional adapter, supports 1 x 18650 battery or 2 x 16340/CR123A batteries
  • Memory function
  • IP68 waterproof
  • 2 meters of shock resistance

Dimensions: 1.57″ *1.00″ *6.05″ / 40*25.4*153.6mm
Weight: 4.66oz / 132.2gr (without battery)


The above parameters (laboratory tests using CYANSKY BL2150U 5000mAh 21700 Li-ion rechargeable batteries) may vary depending on the flashlight, battery and environment.

arrives in a blue / gray cardboard box with the classic writings that show the main characteristics that distinguish it. Inside the package we find, in addition to the K3 v2.0 with Clip inserted and with the 5000 mAh 21700 rechargeable battery inside, the USB-C charging cable, the holster, the lanyard, 2 spare O-rings, spare rubber switch, manual and warranty.



The supplied holster is in cordura with tear-off opening. It is well made and protects the K3 v2.0 well once inserted inside.

The sales package is complete with everything needed to use the flashlight immediately. Already inserted in the K3 v2.0 we find the well-made Clip firmly on the flashlight body which allows easy insertion in jeans.

The rechargeable battery included in the sales package is a 5000mAh protected Lithium in 21700 format (BL2150U) marked CYANSKY. CYANSKY K3 v2.0 can also be used with other 21700 batteries without problems.


In the upper part of the battery, near the positive, there is the USB-C format charging connector. It took me about 3 hours and 15 minutes to recharge the battery. At the end of the charge the voltage was 4.22V.
The CYANSKY BL2150U battery has a notification LED in the center of the button on the positive. When the battery is being recharged, the LED is red, while when the charge is complete it turns green.

These are some of the characteristics of the battery:

- High capacity of 5000mAh
- Voltage 3.6V
- Charging via charger 1A recommended, 5A maximum
- Charging via USB cable Maximum output 8A
- USB-C charging port
- 500 charge and discharge cycles
- Built-in intelligent protection circuit
- Steel shell riveting processing technology
- Weight 73g
- Dimensions 21mm*70mm
- Suitable for Cyansky K3, Cyansky P25, Cyansky K3-I8, Cyansky H3, Cyansky H5


has good build quality, with good thicknesses, no edges or construction residues.
K3v2.0 is 153.6mm long with a weight of 206gr (with battery and clip). K3v2.0 holds well in the hand with good grip due to the design of the body, and consists of two parts: head with body and tail. The writing on the torch is well made and clearly legible.




On the head
of the CYANSKY K3 v2.0 we find a smooth aluminum reflector with the Luminus SFT-40-W LED in the center which allows the K3 v2.0 to reach a remarkable beam distance of almost 700 meters with a brightness, according to the data of table, of 2000 lumens.

DATA SHEET: is external)

The lens,
made of tempered glass, with double-sided coating and high hardness, comes protected by a transparent plastic.


On the bezel
in the head we find three high-hardness zirconium beads, which can easily break glass or hard materials.


The side button, with which we will manage the available levels, is slightly raised and has a low-noise click.
In the center of the button we find a notification LED that lights up to tell us the battery charge status when the power is on. The indicator will turn off after 3 seconds.

Battery charge level
Green light: 76% -100%
Flashing green light: 51% -75%
Red light: 26% -50%
Flashing red light: 0%-25%.



When the battery is low
, the power indicator flashes red continuously 3 times per second and the work light flashes 3 times every 3 minutes to remind us to replace the battery.
When the flashlight detects that the battery voltage is lower than 3.0V, the flashlight will lower the current working mode to LOW mode.

The central body
of the CYANSKY K3 v2.0 has a horizontal striped texture to increase the grip by favoring the grip with the hand.

At the back
of the tube we find the square threads that arrive well lubricated. There is also an O-ring seal for protection against water and dust. CYANSKY K3 v2.0 has waterproof and dustproof rating according to IP68 (2 meters submersible).


At the two poles
, for contact with the battery, we find a plated spring at negative and positive pole, suitable for withstanding the recoil blows of rifles. The K3 v2.0 has a mechanical protection against reverse polarity.


The only unscrewable part of the K3 v2.0 is the tail cap. On the cap it is then possible to insert the lanyard supplied with the torch.

At the bottom
we find the mechanical tactical button to turn the flashlight on or off. The button also has a Momentary On function. To operate it you need to make a fair amount of force and the click is noisy. The shape of the tail cap protects against involuntary ignition. K3 v2.0 is tail standing capable.


near other flashlights.


From left
: CYANSKY K3 v2.0, Nitecore P20i, Acebeam P16, Acebeam X80 e Speras T3R.



The user interface of CYANSKY K3 v2.0 is simple. The flashlight has memory (excluding the Strobe level). K3 v2.0 has two switches, one on the tail and one on the side, four brightness levels and two special modes, Strobe and ECO.

General Mode:

: 30 lumens
MED: 150 lumens
HIGH: 450 lumens
TURBO: 2000 lumens

Special Mode:

: 2000 lumens
ECO: 2 lumens



  • Tap the tactical tail switch to momentarily turn on the flashlight. Release and the flashlight will turn off.
  • Fully press the tactical tail switch to turn the flashlight on/off. The flashlight will turn on in the saved mode.
Switching to general mode
When the power is on, press the electronic switch on the body within 0.5 seconds to switch the general mode: LOW - MED - HIGH - TURBO.
Switch to special mode
STROBE: With the flashlight on, press the side switch to enter Strobe mode.
ECO: With the torch off, hold down the side switch while pressing the tail switch.
Memory function
The flashlight has a memory function. When the flashlight is off, it will save the previously used mode (STROBE mode excluded).
High temperature protection
After working in TURBO mode (2000 lumens) for 90 seconds, the flashlight will automatically dim to 800 lumens to avoid overheating. Then it will adjust the brightness according to the temperature.
When the product temperature is higher than the safe value, it will reduce the brightness of the product through temperature control to avoid product damage and user injury.



The beam
of the CYANSKY K3 v2.0 has a constant brightness, good white coloration without evident artifacts with a pronounced and wide hotspot and an exploitable and bright spill.


has a powerful beam that illuminates well up to medium / high distances. The values in candela, found by me with a measurement at 5 meters, are slightly lower than those declared by CYANSKY (Low is higher), but still higher than those of other competitors.

Turbo = 107500cd
High = 26650cd
Med = 9628cd
Low = 1681cd


From the tests made with the OPPO Light Master Pro, two meters away from the sensor, the value of the CCT color temperature and the Ra color rendering varies, as we have already seen, according to the selected light level. Let's see some values taken with this tool:

In TURBO (2000 lumens) I measured 6466 CCT and 69.7 Ra. – Duv 0.0038
In HIGH (450 lumens) I measured 5968 CCT and 67 Ra. – Duv 0.0084
In MED (150 lumens) I measured 5850 CCT and 66.2 Ra. – Duv 0.0098
In LOW (30 lumens) I measured 5767 CCT and 65.9 Ra. – Duv 0.0107

With a FLIR thermal imaging camera I detected how the heat is distributed on the CYANSKY K3 v2.0 in Turbo mode (2000 lumens) after 2,5 minutes and 5 minutes from switching on.


The Runtime were done in an internal environment with a temperature of about 15°C, using the supplied battery, a Cyansky 21700 5000mAh, a fully charged.

I would like to point out that the values expressed by the graphs must be evaluated above all as a reference because they are made with means and conditions different from those used in the laboratory.

CYANSKY K3 v2.0 has temperature control to avoid overheating which can cause damage to the flashlight or injury to the user. However, I had no problem holding the K3 v2.0 when using it on High or Turbo.
The tests were done by putting the CYANSKY P25 v2.0 in TURBO mode (2000 lumens), in HIGH mode (450 lumens) and in MED mode (150 lumens). The measurement is made with the LX1330B Luxmeter with measurement (lux/1m) during the discharge phase.
The runtime values are similar to those declared by CYANSKY except the Med level of 150 lumens lasting just over 13 hours. Excellent adjustment.


The first 5 minutes:


VIDEO Review


CYANSKY K3 v2.0 is a well built flashlight with a powerful and concentrated beam that reaches medium / long distances. The dimensions remain compact and allow a good grip even for those like me who have small hands.
The sales package of the CYANSKY K3 v2.0 is complete with everything needed to use the flashlight immediately; do not miss the always useful lanyard, the essential but well-made case and the Clip.
In K3 v2.0 I liked the coloring of the beam and I appreciated the adjustment found during the discharge tests (runtime).
CYANSKY K3 v2.0 can be powered by non-proprietary 21700 format batteries which is increasingly rare but appreciated by many users while the user interface is easy to remember but, given the type of flashlight, I would have appreciated the possibility of quick activation of the Turbo and the Strobe.
CHYANSKY K3 v2.0 is definitely recommended for activities that require a long range beam such as search and rescue, police force, hunting etc.
Thanks for reading the review.

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