Klarus xt21x complete and detailed review

Klarus xt21x

Introduction Klarus XT21X

Klarus XT21X is among my best choices for compact tactical flashlights. I like this 2019 tactical light for its advanced features. And besides, it is not every day that you find a light with two tactical switches. Also, the 4000 lumens output is an absolute delight for tactical flashlight enthusiasts.

Klarus has a legacy of producing high-quality tactical lights. The XT21X light is no different as it is made of aircraft quality aluminum material. In addition I like the horizontal knurlings that form diamond shapes on the light’s body.

The Klarus XT21X is a durable and water-resistant light for security and law enforcement personnel. It is longer than the previous XT11X flashlight that offers a 3200 lumens output. As mentioned before, the XT21X has an output of 4000 lumens for the turbo and strobe modes which is more.

In this article, I am going to write my review of the Klarus XT21X. I hope that it will help you decide if this is the best light for you and the features to look forward to.

Similar Products

Inside the Box

Klarus always put an effort to include a user manual to guide on their flashlight specs. You will find all the details on the well-designed packaging box. Klarus also provides a free battery with its lights and other accessories.

The user manual will guide you on how to switch from one mode to another. But, there is more to appreciate about this high-quality flashlight. It comes with all the accessories that you need to use it.

You will find the following accessories in the Klarus XT21X packaging box:

  • Klarus XT21X flashlight

  • Micro-USB charging cable

  • Lanyard

  • Pocket clip

  • Extra O-ring

  • Branded holster

  • User manual

  • 1 21700 5000mAh battery

Klarus XT21X flashlight is one of the tactical lights with long runtimes. I was impressed by the battery performance when testing this light. But, I think that Klarus would have included more accessories such as a spare battery for a light worth more than $100.

Below you can see the box and what was included.

xt21x - box2
Klarus xt21x - box
Klarus xt21x - box content 2
xt21x - box content

Diffrence Between Previous product

Klarus has been upgrading the brightness output of their tactical lights. XT21X’s predecessor, the Klarus XT11X, has a lower output of 3200 lumens. Klarus XT21X has a higher output of up to 4000 lumens. I think this is a brilliant upgrade.

The earlier version, the XT11GT, was slightly shorter and with a much lower brightness output than the 2019 XT21X. It offers up to 2000 lumens. You can see that Klarus has been working on improving the brightness of their tactical lights output.

The XT11X also comes with a tail cap switch. On the other hand, the XT21X has two tail switches. It is an excellent upgrade that has transformed the XT21X ease of use.

Again, the Klarus XT21X flashlight has improved its high jump from one mode output to another. For instance, the XT11X has a high mode of 400 and a turbo mode of 3200. It is difficult for your eye to adjust to such a quick jump.

I still think that Klarus needs to work on these high jumps. Even with the XT21X flashlight, you will get from Turbo mode of 4000 lumens to a high mode of 1200 lumens.

Klarus XT21X uses a 21700 battery, while the XT11X uses 18650 or 2 16340 batteries. It is a bit flexible because you can also use the CR123A batteries. This is a huge difference between these two Klarus lights.

Both XT21X and the XT11X lights use CREE XHP70.2 P2 LEDs.

User Experience

Product Overview of Klarus XT21X

I love tactical flashlights not because I work for the military or anything but because there are reliable. Instead of spending multiple $10 for low-quality flashlights, get a durable tactical light. They are also reliable for personal or work use.

Klarus XT21X flashlight stands out from its competitors for its compact nature. It is amazing how much output you can get from a 6.5 inches flashlight. Klarus XT21X is slightly taller than the Olight Warrior X Pro tactical light and among its top competitors. It is also taller than the previous XT11X flashlight.

I think that a Turbo and Strobe mode of 4000 lumens output is very impressive. Besides, the light is powered by a 21700 5000mAh battery which can go up to 200 hours.

What’s even exciting about Klarus  XT21X is that it comes with two tail switches. It is a nice feature for people who want to use the light for tactical purposes.  You can easily change from the Outdoor mode to the Tactical mode in seconds.

XT21X also comes with a side switch! This makes it a total of three switches, and the side switch has an in-built memory. It will get you back to the last mode that you used. I will discuss this in the user experience section.

Klarus XT21X does not need a lot of time to learn how to operate. Besides, it comes with a well-detailed box and a user manual.

If you are worried about your flashlight’s safety, the holster and the pocket clip will help. The pocket clip is firm, but it does not rotate. But, I like that it leaves a part of the flashlight out of your pocket. I find it enough to ensure safety, especially when you are outdoors.

xt21x - specs

Built Quality of Klarus XT21X

Klarus, Fenix and Nitecore have never disappointed me with their tactical flashlights. The XT21X has an aircraft quality aluminum body. Not only is the material durable, but the glossy anodizing makes this flashlight very attractive. 

The horizontal knurling patterns form diamond shapes across the aluminum body. The side switch has an LED battery indicator at the center. I have seen this with the modern tactical flashlights these days. I think it is a design-effective feature.

The micro charging port has a cover, which ensures that your tactical light stays dust and water-resistant. XT21X tactical light also supports fast charging. It takes about 3 hours to charge the light to 100%, just as impressive as its runtime.

The sides switch on the XT21X flashlight has an in-built memory program. You can quickly go back to the mode you were using when turning the light off.

For safety purposes, this light also has the head glued to its body. You can only unscrew the tail cap from the body when inserting the battery. This is an essential figure for the light to be dustproof and waterproof.  I have actually dropped my light accidentally a couple of times, and it didn’t flicker or go off.

Klarus XT21X flashlight also feels quite balanced in my hand. The body and the head are balanced, and besides, it is a lightweight light.

Thermal protection system


Klarus recommends the XT21X tactical light for security and law enforcement officers. It has a high brightness output powered by the CREE XHP70.2 P2 LED. At the same time, this light is suitable for the outdoors, thanks to its rugged quality.

However, I find the runtime for the Turbo mode too short. You can only use this mode for one minute before dropping to a high of 1200 lumens. Klarus flashlights have always had huge jumps between the modes.

Having three switches allows flexibility. You can turn the light on or off quickly, given the easy access to a switch. XT21X has two tail cap switches; the primary switch and the paddle. The side switch is an excellent feature that lets you flash the light or go back to your last mode.

I like carrying my light in the branded XT21X holster. The holster has a safety cup that holds the light in place. And besides, you can always carry your light safely using the firm pocket clip. Klarus invests in customer satisfaction by providing all these accessories at no additional cost.

You can also use the Lanyard to keep your light safe, especially when you are outdoors. This light is ideal for your hiking, hunting and camping trips.

Let’s now look at the Klarus XT21X flashlight user interface and how to navigate different features.

Klarus xt21x - size

User Interface of Klarus XT21X

If you are looking for a straightforward tactical light, XT21X is a brilliant choice. As with most Klarus flashlights, XT21X is a durable and high-quality light. It offers three switches to allow easy navigation. Besides, Klarus also includes a detailed user manual when shipping the flashlight.

XT21 offers up to 7 brightness outputs and two user settings, the Outdoor and the Tactical setting. The light will be in the tactical settings by default when you half-press the primary tail switch.  A full-press will activate the strobe mode on your flashlight, giving you 4000 lumens output.

If you want to access the Strobe mode in your XT21X quickly, click the secondary tail switch. The tactical setting is designed to give high output. It starts at the High mode of 1200 lumens, and thus you should be careful not to blind someone when turning on your light.

On the other hand, the outdoor mode starts at the lowest mode, the Moonlight mode with 5 lumens output. Compared to XT21X competitors, a Moonlight mode of 5 lumens is a bit high.  But still, it does not take away a point from the light’s performance.

Long pressing the secondary switch will navigate you through the different modes. The most exciting thing about the second switch and the side switch is that they are interchangeable. For instance, if you turn your light in the Low mode, clicking the side switch will automatically take you to the turbo mode.

The side-switch also comes with an LED battery indicator. You can tell that your battery life is depleting when your light displays different colors. Here is the list of colours and battery percentage:

  • Green – 70-100%

  • Yellow/Orange – 30 -70%

  • Red – 10-30%

  • Blinking Red – <10%

Brightness Outputs and Runtime of Klarus XT21X

Klarus XT21X flashlight takes you to another level when it comes to the brightness output. You can access the Turbo or Strobe mode for the highest output of up to 4000 lumens.  The battery runtime is also very impressive, going up to 200 hours when using the low mode.

The XT21X flashlight allows you to use up to 7 modes, even though there is a huge difference between these outputs. The Turbo mode lasts for at least 1 minute and 2 seconds, producing up to 4000 lumens. It then drops to a High mode giving out 1200 lumens. I think that this is still a compelling model, especially for tactical operations.

It takes 2 minutes for XT21X to drop to a Medium mode with 400 lumens output.  The light will stay on this mode for 6.5 minutes before dropping to a Low mode with 100 lumens brightness. The low mode can take up to 21 hours before it drops to the Moonlight mode with 5 lumens output. The Moonlight mode can last up to 200 hours!

Here is the table of Klarus XT21X brightness modes, output, and battery runtime:



Brightness Output

Battery Runtime


4000 lumens

1.2 minutes


1200 lumens

2.3 minutes


400 lumens

6.5 minutes


100 lumens

21 hours


5 lumens

200 hours


4000 lumens

2.4 minutes


100 lumens

63 seconds


Klarus designed the XT21X with huge gaps between the brightness output settings. However, it is still an ideal light for tactical light enthusiasts.

4000 lumens tactical flashlight

Klarus XT21X is best for

Are you a flashlight enthusiast or collector? The Klarus XT21 is an ideal light to add to your collection for tactical lights. Klarus recommends this light to law enforcement and security personnel. It would also be a great option to bring to your camping and hiking trips.

If you do enjoy night hunting, this tactical light offers powerful output and overall performance.  The runtime is also impressive, as well as the fast charging feature. I charged my light in 3 hours and 20 minutes.

Klarus XT21X is also IPX-8 rated, which means it is both waterproof and dustproof. There is nothing you cannot do with this piece.

Pros and Cons of Klarus XT21X


  • Impressive output levels giving up to 4000 lumens

  • It comes with three switches to allow flexibility when changing the modes

  • You can choose to use the Outdoor or Tactical settings depending on the activity at hand

  • The light has active thermal controls

  • 21700 battery allows longer runtimes and better performance

  • It comes with all the accessories you need to use the light



  • The turbo mode only lasts for a minute, making it almost useless for security and law enforcement personnel

  • Huge output gap between the 5 different output modes

  • It does not come with an extra battery

Our Rating

On a scale of 0-10, our rating for the Klarus XT21X flashlight is 8.5. While it presents different mode outputs with an impressive user interface. It is easy to select your preferred mode using the three switches. However, the 1.5 points are for the battery runtime, especially for the high and turbo mode.

I expected this light to provide a full tactical experience, and it did. It is a total delight, and I am excited to add this to my tactical lights favorites.

5000 mhw battery

Where to Buy

Easiest way is to order it from Amazon. But you will also find it from most of the camping and hunting stores.

Final Verdict to Klarus XT21X

Klarus XT21X is a great flashlight for those who want a multi-purpose light. It is easy to use, and you can select when to use the tactical mode or the outdoor mode. I don’t work in security, so yes, this was a great feature for me.

For a flashlight going for slightly over $110, XT21X is an excellent flashlight. The output is excellent and can be used in rural areas, farms, camping, and hunting. I think Klarus should have added an extra battery to meet this price.

My only regret is that the Turbo Mode lasts for only a minute. Nevertheless, XT21X is definitely a great upgrade from the XT11X.

Let us know what do you think about our reviews!

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