I was going through all of the 21700 flashlights that I reviewed in the last few months, and there are some incredible tactical flashlights. So I thought I would compile a list of the brightest flashlights that run on 21700 batteries. These are quickly becoming my favorite lights. They range in size, output, and many more details. So let’s get started.
What is a 21700 Lithium-Ion Battery?
For years now we’ve been seeing many LED flashlight powered by 18650 lithium-ion batteries. However, we’ve started seeing flashlights that run on higher-capacity batteries. We’ve seen flashlights run on 26650 batteries. These batteries are quite a bit bulkier than 18650s and therefore the LED flashlights themselves are a little difficult to carry with you everywhere. These flashlights are also difficult to mount on any weapon and you can’t guarantee that you’ll find a gun mount that’s compatible with them.
21700 batteries are slightly thicker and longer than 18650 batteries and a lot more powerful. This means that a 21700 flashlight can remain a similar size to that of an 18650 flashlight while providing a higher output and longer run times. With 18650 batteries we’ll often see mAh capacities at around 3500 milliamps give or take. However, with 21700 batteries we can see higher capacities of 5000 milliamps which is a lot of power.
The Best 21700 Flashlights
I had a tough time narrowing this down and I wanted to make it 5 flashlights, but instead it’s going to be 6. I’ll try to keep it brief, however. I’ll summarize the features of each of these flashlights and make sure to link to my reviews so you can see more detail if you want to. Let’s get started.
Nitecore i4000R – 4400 lumens
The first one we’re going to talk about is the Nitecore i4000R tactical flashlight. This flashlight features four LEDs delivering 4400 lumens and features a very floody beam. The flashlight itself is a little over 6 inches in length. So it’s possibly a little too big for everyday carry, but it does come with a really cool belt clip to make it easier to carry.
The i4000R features dual tail switches, which is my preference when it comes to a tactical flashlight. It also features a momentary-on, instant strobe and instant turbo. The i4000R LED flashlight features 5 brightness levels ranging from 2 lumens to 4400 lumens as well as a strobe. You’ll also have a mode memory function which is always a plus.
It is a USB-C rechargeable flashlight that features a rotary USB port cover. It’s a really unique idea and I really like the rotating cover. I find it a lot easier to deal with than the silicone covers you have to push into the flashlight really hard. As for batteries, it does require a proprietary 21700 battery, but you can use two CR123 batteries with the included magazine as well. So you do have some choice with the battery situation, but I would recommend using a 21700 battery so you can get better run times and higher output. So make sure to check out the Nitecore i4000R tactical flashlight.
Nitecore E4K 4400 lumens
The next one is fairly similar to the i4000R. It’s the Nitecore E4K flashlight and it also has four LEDs and delivers 4400 lumens with a very floody beam. This one is more suitable for everyday carry at a little over 4 and 1/2 inches in length and features a two-way pocket clip.
Operating the E4K tactical flashlight, you have a single side switch with a few different shortcuts. You have a momentary turbo, an ultra low, and a strobe or a turbo depending on which mode you have the flashlight in. There are two modes: Tactical, which gives you a shortcut to strobe, and Daily, which gives you a shortcut to Turbo. So it’s nice being able to choose between those.
The E4K flashlight features five brightness levels that range from 21 lumens to 4400 lumens as well as the three flashing modes. The turbo is more of a burst turbo and isn’t going to last you for very long so keep that in mind. However, the lowest brightness level has a maximum run time of 700 hours which is the best runtime of all the flashlights on here.
You can use a 21700 battery or two CR123 batteries using the included battery magazine. It comes with an included USB-C rechargeable 21700 battery. The light itself is not a rechargeable flashlight so the fact that the battery is USB-C rechargeable is a huge plus. Make sure to check out the Nitecore E4K everyday carry flashlight.
Klarus XT21X 4000 lumens
The Klarus XT21X flashlight is certainly a beast, delivering 4000 lumens and being almost 6 and 1/2 inches in length. That’s a bit big for me to be an everyday carry flashlight, but that’s really more preference. It has a good balance between a focused beam and a flood beam so you’re going to be able to see far into the distance while also seeing around you
This flashlight has a lot going for it. It has a triple switch design with dual tail switches and a side switch that functions independently so you can choose how you want to operate the light. The tail switches give you a shortcut to momentary on, instant turbo, and a strobe or instant low depending on which setting you have the flashlight in. The side switch gives you a mode memory function as well as a straight to low which is great.
The two programmable modes are the Tactical Mode where the tail switch gives you an instant strobe and then the Outdoor Mode where the tail switch gives you an instant low. The side switch stays the same in both settings. You also have 5 brightness levels ranging from something to something, a strobe, and an SOS mode.
The XT21X can only run on a 21700 battery but it is micro USB rechargeable. There’s a lot going on with this flashlight. If you’re wanting an extreme tactical flashlight, check out the Klarus XT21X.
Olight Warrior X Pro 2250 lumens
The Olight Warrior X Pro is a really unique tactical flashlight. It delivers 2250 lumens and has a 600 meter beam distance so you’re going to see an extremely focused hotspot with this flashlight. It’s nearly 6 inches in length so I wouldn’t consider it everyday carry. However, it’s still compact that it would be easy enough to take with you on duty or trips.
The X Pro tactical flashlight features two brightness levels which is high at 225 lumens and low at 300 lumens. So the high is more of a burst turbo I would say. It’s going to last for about 2 minutes and then drop down to 1000 lumens which is still a great amount of light. There is no strobe with this light so keep that in mind if you’re considering purchasing it.
The user interface is extremely simple with this light and that means it’s super easy to learn. It has a single tail switch but you have a half press to low, full press to high, and hold for momentary on. It’s quick to learn and very simple.
Warrior X Pro is a rechargeable flashlight and uses a magnetic charging function with 2A fast charging. So it charges very quickly. It does require a 21700 proprietary battery along with a proprietary magnetic cable. However, magnetic charging it’s always a great option as you don’t need to fumble with cords. You just attach the flashlight and it’s good to go. If you’re wanting a mini thrower, make sure to check out the Olight Warrior X Pro tactical flashlight.
JetBeam KO-02 1800 lumens
We’re onto another compact everyday carry flashlight, the JetBeam KO-02. This little pocket beast delivers 1800 lumens has a 270 meter range which means you’re going to get a pretty defined hotspot.
Its operation is quite simple with a single side switch. The only shortcut you have on this light is a double press for strobe and that’s it. It has brightness levels ranging from 12 to 1800 lumens along with a strobe. Like I said, there’s not much to this flashlight at all so if you want a simple flashlight and don’t need a bunch of shortcuts and features, this is a great tactical flashlight.
The JetBeam KO-02 is a USB-C rechargeable flashlight which is always great to see. It’s also compatible with a 21700 battery, a 20700 battery, and an 18650 battery. So you get the most options with this light in comparison to any other light on this list. If you want a straightforward everyday carry flashlight, check out the JetBeam KO-02.
Fenix TK22 V2.0 1600 lumens
Fenix TK22 V2.0 last flashlight on this list. The Fenix TK22 V2.0 is a durable and rugged tactical flashlight. To deliver 1600 lumens with a maximum distance of 405 meters so it’s going to give you a wonderfully focused beam and good distance to it. It’s about 6 inches in length which is a bit big for everyday carry, but perfect for hunting trips and taking with you on trips.
The user interface is really simple with a tail switch that turns the flashlight on and off and gives you a momentary on. You also have a side switch that accesses the brightness levels and gives you access to strobe. The brightness levels range from 30 lumens to 1600 lumens, which is a very nice range for a tactical flashlight.
This flashlight is compatible with a 21700 battery or an 18650 battery using the included battery holder. With any tactical flashlight, it’s always great to see compatibility with multiple battery types. So I’m happy to see that the TK22 V2.0 is compatible with an 18650. If you’re looking for an awesome Fenix tactical flashlight, check out the Fenix TK22 V.0.