Klarus XT21X - 4000 Lumens

  • Klarus XT21X - 4000 Lumens - FZ-KLXT21X
  • Klarus XT21X - 4000 Lumens - FZ-KLXT21X
  • Klarus XT21X - 4000 Lumens - FZ-KLXT21X
  • Klarus XT21X - 4000 Lumens - FZ-KLXT21X
  • Klarus XT21X - 4000 Lumens - FZ-KLXT21X
  • Klarus XT21X - 4000 Lumens - FZ-KLXT21X
  • Klarus XT21X - 4000 Lumens - FZ-KLXT21X
  • Klarus XT21X - 4000 Lumens - FZ-KLXT21X
  • Klarus XT21X - 4000 Lumens - FZ-KLXT21X
  • Klarus XT21X - 4000 Lumens - FZ-KLXT21X
  • Klarus XT21X - 4000 Lumens - FZ-KLXT21X

View the Klarus XT21X on Amazon

Get ready for one of the brightest tactical flashlights for 2019! Klarus has gone above and beyond in creating the Klarus XT21X tactical flashlight. It delivers an incredible 4000 lumens of power that will vanquish the darkness easily. This power is partly thanks to the CREE XHP70.2 P2 LED that the flashlight is equipped with and partly thanks to the included Klarus 21700 lithium ion battery with a 5000 mAh capacity. This is the first Klarus flashlight to use this particular lithium-ion battery and it really delivers in power. Not only does the XT21X have a 4000 lumen output, it also features a maximum beam distance of 316 meters, allowing you to see far into the distance while illuminating the entire area in front of you.

This tactical beast is a compact and lightweight flashlight that can easily be attached to your pocket using the pocket clip or carried in its included holster. It features a triple switch design with two tail switches and a side switch that functions separately. You can choose how you'd like to operate the flashlight at any given time. With its seven outputs, it’s extremely versatile and ready for anything. It features five brightness levels that range from 5 lumens to 4000 lumens as well as a strobe mode and SOS mode. On the lowest brightness level, the moonlight mode, the XT21X has a maximum runtime of 200 hours making it perfect for professional work and outdoor use.

To add to its versatility, the XT21X features two programmable settings: the Tactical Setting and the Outdoor Setting. In the Tactical Setting you'll have access to a One-Touch Turbo and a One-Touch Strobe. This is a great setting for law enforcement, security, or just wanting to be prepared. In the Outdoor Setting you have access to a One-Touch Turbo and a One-Touch Low. This is an excellent setting for general use, outdoor use, and professional use. You can also switch between settings at any time, giving you more options on how you'd like to use the flashlight.

The Klarus XT21X is a USB rechargeable flashlight making it a convenient tool to have. 2A USB fast-charging makes it quick to charge your flashlight and you can check the charging indicator to know the status of the battery. The XT21X is also an extremely durable flashlight. It’s impact resistant up to 1 meter and waterproof up to IPX8 standards. It also has several protections in place to ensure that the flashlight is safe including over-current protection, over-charge protection, thermal protection, reverse polarity protection, and over-voltage protection. If you’re looking for the most powerful tactical flashlight that’s also rechargeable and compact, you’ve found it in the Klarus XT21X.


  • Equipped with a CREE XHP70.2 P2 LED, delivers a maximum output of 4000 lumens and maximum beam distance of 316 meters
  • Triple switch design - dual tail switches and side switch
  • Seven outputs
    • Turbo - 4000 lumens - 1.2 hour runtime
    • High - 1200 lumens - 2.3 hour runtime
    • Medium - 400 lumens - 6.5 hour runtime
    • Low - 100 lumens - 21 hour runtime
    • Moonlight - 5 lumens - 200 hour runtime
    • Strobe - 4000 lumens - 2.4 hour runtime
    • SOS - 100 lumens - 63 hour runtime
  • Maximum runtime of 200 hours
  • Two programmable setting
    • Tactical Setting: One-Touch Turbo, One-Touch Strobe
    • Outdoor Setting: One-Touch Turbo, One-Touch Low, SOS
  • USB rechargeable
  • 2A USB fast-charging
  • Charging indicator
  • Compatible with 1 x 21700 battery
  • Intelligent Temperature Control System
  • Over-current protection, over-charge protection, reverse polarity protection, and over-voltage protection
  • Impact resistant up to 1 meter
  • Waterproof up to IPX8 standards

Included Accessories:

  • Klarus 21700 li-ion battery
  • Holster with protective cap to prevent accidental illumination
  • USB charging cable
  • Lanyard
  • Removable Pocket Clip
  • Spare o-ring

View the Klarus XT21X on Amazon 


Max  Output: 4000 lumens

Max Beam Distance: 316 meters

Max Runtime: 200 hours

Battery: 21700 (5000mAh)

Work Voltage: 2.5 - 6.4V

Waterproof: IPX8 (2 meters submersible)

Lighting Levels: Turbo/High/Medium/Low/Moon/Circle

Weight: 158g / 5.57oz (without battery)

Dimensions: Head Diameter - 41.0mm (1.61"), Body Diameter - 27.5mm (1.08"), Length - 161.0mm (6.34")

Overall Customer Rating of 5 Reviews:
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Incredible power

Product Reviews:
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My first over 2000 lumen flashlight and I’m impressed. TheXT21X is a well made light. All the functions are easy to command in both side and back switch. Light throw is amazing, this thing lights up my yard, my neighbors yard and a few yards to boot. This light will get hot pretty quickly, after about five minutes you’re going to want to back it down from 4000 lumens, which is alright since you have 5 different settings. Time can only tell on durability, but having a 5 year warranty backing it up helps. I wish they would come up with a nice polymer holster that could be adjusted for more than one light. I give it four stars, because they need to work on heat dissipation other than that I love it. Nice carry light that will definitely blind any attackers that come you way.

WOW!!! Very Powerful!!!

Product Reviews:
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Klarus latest innovations in tactical flashlights quite amazing. The company's entry into the 21700 battery powered flashlight is versatile and extremely effective.Very effective in ANY SITUATION where a strong powerful beam of bright light is needed. Let's take a detailed look this powerful handheld illumination device.

The presentation of Klarus XT21X box is great. The quality of box is on par with Apple and Samsung phone retail boxes.The construction is very thick material. Not flimsy cardboard. Pearl White matte finish with picture of flashlight and hand rendered picture soldier/officer gives a great visual appearance of Klarus XT21X. The box presentation includes all pertinent information about the XT21X. Klarus company warranty. information, accessories included with flashlight, and Industry ANSI Specifications.

What comes in the box :

Klarus XT21X Flashlight
Klarus branded 21700 5000 mAh branded battery
Pocket Clip
Spare " O " ring
Micro USB charging cable.
Instruction manual in different languages
Klarus branded lanyard
Neoprene holster with anti accidental turn on prevention.
The base of holster has cup at bottom to prevent light accidentally activation " on " when carried in holster.

The build quality on this flashlight is TOP NOTCH. Made of Aerospace Aluminum Alloy. The hard anodized type 6061-T6, Mil-Spec HAIII protects flashlight from EXTREME environments. The CNC machining is EXCELLENT. CNC Milling of heat surface area grills helps aid in dissipation of tremendous heat produced by this light. New type of diamond knurling helps aid in grip of flashlight in hand. . Dual firm brass springs on tail cap and head area greatly aids in conductivity from battery. Also helps battery from rattle or recoil if gun mounted. O rings seals prevent any type of moisture entrance into flashlight. The front of flashlight head is encased by a stainless steel strike bezel. The strike bezel protects Anti Reflective coated lens. Stainless steel bezel can be used DEFENSIVE TOOL in case of emergency. Fend off attackers, use as STRIKING TOOL in ANY DANGEROUS situation. The pocket clip is rugged and not flimsy so flashlight can be attached easily with very little effort. The pocket clip hold has firm grip once attached.

The Engineering is WELL DESIGNED with emphasis on safety.

Intelligent Thermal Protection System(ITS): monitors and auto-adjusts outputs in real time. To protect LED and components from overheating and damage.

Intelligent Charging System (ICS): Micro-USB charging port with real-time monitoring to prevent overcharging, over-discharge protection, high current protection, high temperature protection.

The switch indicator ring illuminates different colors so visually one can see battery power life status.
Green light indicates : 70% to 100%
Orange light indicates : 30% to 70%
Red light indicates : under 30%
Red flashing light indicates : less than 10%: severely low power needs recharging.

Reverse polarity protection : protects damage of flashlight if batteries are inserted backwards.
Tail and side switches can be put out on " lock out " mode. Lock out mode could be accessed by pressing switch for 5 seconds to activate " lock out " feature. The other way to activate " lock out " feature is manually unscrewing tail cap 1/4 turn from full tightness.The safety feature prevents accidental turning on of light, saves battery drains from storage/ travel, and avoiding serious eye injury.

The Klarus XT21X manufacturing specifications are clearly indicated with very detailed information about flashlight.

The LED light source : CREE XHP 70.2 P2 LED with lifespan of 50,000 hours
6500K Cool White light beam
Output : 4000 lumens
Working Voltage: 2.5V-6.4V.
Reflector: Orange Peel. For balanced dispersal of light beam
Anti Reflective tempered glass coating lens. Scratch resistant.
Dimensions: Head – 41.0mm (1.61”) diameter Body – 27.5mm (1.08”) diameter Length – 161.0mm (6.34”)
Weight: 158g (5.57 oz )

Klarus XT21X specifications as per ANSI/FL1 standards.

The flashlight has 5 light mode levels and 2 flash modes.
Turbo : 4000 lumens Run time : 1.2 hours Candela : 24964 Beam Distance : 316 Meters
High : 1200 lumens Run time : 2.3 hours Candela : 7400 Beam Distance : 172 Meters
Medium : 400 lumens Run time : 6.5 hours Candela : 2450 Beam Distance : 99 Meters
Low : 100 lumens Run time : 21 hours Candela : 600 Beam Distance : 49 Meters
Moonlight : 9 lumens Run time : 200 hours Candela : 30 Beam Distance : 11 Meters

The 2 flashing modes include Strobe and SOS
Strobe : 4000 lumens Run time : 2.4 hours
Sos : 100 lumens Run time : 63 hours

IPX68 Rating:: Waterproof : Water submersible to 2 meters
Impact Resistant : 1 Meter

The light has 2 modes programmed for use in different situations
Tactical Mode : Law Enforcement, Military
Outdoor Mode : Outdoors, Every Day Carry
Changing between Tactical and Outdoor Modes : Press side switch and paddle rear switch simultaneously to switch from the different modes

The orange peel reflector design disperses light beam evenly with great lighting whether near or far distances. The center hot spot is evenly dispersed with VERY LITTLE light artifacts. The hot spot is not tight focused and decent sized allowing for good throw distance and flood of light beam. Light beam is Cool White and pleasant to eyes.

Operation of light is controlled by 3 switches.
Tail cap Main Switch
Paddle rear switch
Front Side Switch

The user interface is pretty simple and can be controlled by any one of the 3 switches.

In Tactical Mode.

Tail Cap Main Switch: Gentle half press for momentary " Turbo " Full press click locks in full " Turbo "

Paddle Rear Switch : Full press for full " Strobe ". Once light is " on " pressing Paddle Switch cycles through turbo, high, medium, and low outputs.

Front Side Switch :Short press to activate " on ". Short press again to cycle thought light outputs. The sequence is turbo, medium, low. Long press turns light " off ". Double click for Strobe. Double click again for SOS . Standard click returns to regular mode.

In Outdoor Mode

Tail Cap Main Switch : Gentle half press for momentary " Turbo " Full press click locks in full " Turbo "

Paddle Rear Switch : Gentle half press for momentary " Moolight " Full press for 3 seconds locks in full " Strobe ". Once light is " on " pressing Paddle Switch cycles through low, high, and turbo light outputs.

Front Side Switch :Short press to activate " on ". Short press again to cycle thought light outputs. The sequence is turbo, medium, low. Long press turns light " off ".Double click for Strobe. Double click again for SoS. Standard click returns back to regular mode.

Now onto the durability/ torture tests to see engineering and build quality.

The Klarus XT21X is rated at IPX68. Waterproof up to 2 meters( 6 feet ). Submerged flashlight swimming pool. Left underwater for 1.75 hours. Retrieved from pool unscrewed tail cap for visual inspection. Completely dry. No sign of water entrance into light. Turned on light. Cycled through all light modes with NO PROBLEMS.

The impact resistance rating is 1 meter( 3 feet ). Dropped light from shoulder height 3 times. 1 drop on side, 1 drop on stainless strike bezel. 1 tail cap Then took light to University concrete bleechers.. Smashed light on concrete surface 3 times. A few minor cosmetic nicks BUT NOTHING MAJOR. Turned on light. Light cycled through all outputs with NO ISSUES.

The crush test really showed how well built the Klarus XT21X is. Ran over flashlight with van. The vehicle used is Toyota passenger van.. Ran over light 12 times. 4 times in drive completely running over light. 4 times in drive mode. 4 times in reverse mode. Ran over light on 2 different surfaces. Asphalt and Cement Retrieved light. Turned on light. Cycled through all light outputs like A CHAMP!!

The Klarus XT21X is built like a TANK. Extremely durable and SUPER tough in ANY HARSH ENVIRONMENT.

The XT21X is a EXCELLENT choice for anyone looking for high quality great output flashlight.

In conclusion, Klarus Engineering Design, build material, great quality, and innovative features make them one of the top contenders in the flashlight market today.

For more information on how to get your own. Please visit flashlightz.com


It is NOT DOA. You must further tighten the tail cap!!!

Product Reviews:
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The slightly increased diameter of the body is more comfortable in the hand and this is the first Klarus with a dual switch tail cap where you do not accidentally reduce the output of the light by inadvertently pressing the strobe/adjust button right after you press the main on/off center switch. I like it very much and would love to see a 26650 version. I also want to mention that Flashlitz offers outstanding customer service. in the past they have gone far above and beyond to help me purchase specialty parts.

Klarus XT21X

Product Reviews:
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Nice flashlight I'm impressed.

Southlake, TX

Excellent multi purpose light

Product Reviews:
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I really like this light. 21700 battery for longer run time, an interface that lets me disable the side button and set the two tail cap buttons to turbo and moonlight, and a nice lanyard hole. Super bright, nice beam pattern. Quickly becoming one of my favorites.

Number of questions: 0

FZ Opinion: Most Powerful Compact Tactical Flashlight

Author: Carolyn

We all knew that Klarus would be coming out with a massively powerful tactical flashlight for 2019, but we were not expecting quite so much power when they finally announced the flashlight. The Klarus XT21X is a powerhouse flashlight that is still compact enough that you could carry it around. We were amazed with this flashlight when we finally got it into the store. So let's take a look at the flashlight, what it has to offer, as well as some pros and cons.

4000 Lumens of Intense Power

4000 lumens is nothing to sneeze at. In fact, you'll be blown away by the sheer power of this flashlight. It has a CREE XHP70.2 P2 LED and, coupled with the 21700 battery, you have one amazingly powerful flashlight. The beam pattern on the XT21X is very wide and dispersed. The idea of the XT21X is to illuminate everything around you rather than to pinpoint anything far into the distance. So rather than a more focused beam it definitely has a floodier beam with this flashlight. 

Tactical User Interface

Just like many other Klarus flashlights, the user interface on the XT21X it's incredibly robust. It's built so that any user can operate it the way they would like to. To start with, the XT21X does come with three switches, two tail switches and a side switch that functions independently. So this is going to allow you to use the side switch or the tactical tail switches whenever you feel like it. The switches can easily be locked out to prevent any accidental illumination which is great because you certainly don't want a 4100 flashlight turning on by accident.

So you're going to get a couple different features depending on which switch you use. With the dual tail switches, you'll have a momentary-on, an instant turbo, and an instant strobe or an instant low. With the side switch, you're going to be getting a built-in memory function as well as an instant  low. That mode memory function can be really handy especially with the side switch because it allows you access to the lower brightness levels immediately. For general use, professional use, outdoor use, that feature can be extremely useful.

Multiple Outputs

The XT21X does feature multiple outputs and two programmable settings that you will find in many Klarus tactical flashlights. With the XT21X you have seven total outputs and that will include five brightness levels that range from 5 lumens to 4000 lumens, giving you quite a range. You also have a strobe and an SOS mode just in case of emergencies. The maximum run time using that moonlight mode is going to be 200 hours at most so this flashlight can last you an extremely long time before you need to charge it.

As I said before, this tactical flashlight does have two programmable settings which is a Tactical Setting and the Outdoor Setting. It's important to know that the side switch is not affected in either setting and that the settings will only affect the tail switches. In the Tactical Setting, the secondary tail switch will give you an instant strobe when pressed and held down. It will also allow you to cycle through the turbo, high, medium, and moonlight brightness levels. In this setting, using the side switch, you’ll be able to cycle through all five brightness levels rather than just four.

In the Outdoor Setting on the other hand, when you press down the secondary switch and hold it down, it will enter instantly into the moonlight brightness level. You'll also be able to cycle through all five brightness levels using either the tail switch is or the side switch. Switching between the modes is pretty quick and fairly easy, but I recommend keeping that manual handy just in case.

USB Rechargeable Flashlight

The XT21X is a rechargeable flashlight and features a USB port located just below the head of the flashlight. This makes charging that 21700 battery extremely easy and convenient. While you have the flashlight plugged in, you'll see an indicator glowing around the side switch. It will glow red if it's charging, green when the charging is finished, and yellow if something is interfering with the charging. This indicator also doubles as a battery capacity indicator that will glow a certain color and give you an idea of how much charge you have left in that battery. This indicator is great because you can plan how much will be using your flashlight based on how much battery there is left.

I mentioned this before, but the XT21X does come with a 21700 battery that has a 5000 mAh capacity. It’s an extremely powerful battery and we are excited to see Klarus use is in such a compact flashlight. The flashlight is larger than an 18650 flashlight, but not by too much. It will only run on a 21700 battery, however. This can be something of a downside, especially if you prefer flashlights that can run on multiple battery types.

The XT21X has a lot of safety features in place to make sure the flashlight is long lasting. So you're going to have a thermal protection system which will automatically adjust the output based on the temperature of the flashlight and this is going to protect the LED as well as the internal electronics of the light. It's also crafted from an aluminum alloy and is extremely durable. The XT21X is going to last you a long time and we are extremely impressed with this tactical flashlight.


You have a lot going on with the Klarus XT21X because it was designed to have robust features that allowed it to be used in many different situations. Between the powerful output, multiple brightness levels, programmable settings, and triple switch design, you can use this flashlight however you want to whenever you want to. It does not limit you in any way and that's one of the great aspects of this particular flashlight. The user interface does take a bit of time to learn, so if you're looking for a simple and straightforward flashlight, the Klarus XT21X is not going to fit that ticket. It's also a bit larger and can be clipped onto a pocket but you may feel more comfortable carrying it with the holster. Speaking of the holster, it does feature a little cap in the holster where the tail switch fits in that way the flashlight does not turn on accidentally. That is an awesome holster that's included with this flashlight. If you’re looking for a powerful, versatile, and long lasting tactical flashlight, the Klarus XT21X is it.