Gear Review: FourSevens Maelstrom MMR-X flashlight

I was highly excited to be contacted by FourSevens about reviewing a light powered by an 18650 LiPo cell. I’ve as anyone who has read my previous flashlight reviews knows, I currently carry a modified version of the QT2A-X daily, and have been running it on a 14500 LiPo cell. This light has served me well and is still found in my pocket every day.

I was really intrigued by the possibilities of having a USB chargeable 18650 light. When the MMR-X arrived, I was quite delighted to find that FourSevens was including a number of accessories that allows the user to configure the light in several different ways, depending on the users preferences.

This light is the first FourSevens light to be powered by an 18650 cell.

Specifications for the MMR-X from the FourSevens website:

DIMENSIONS Length: 5.47 inches / Diameter: 1.24 inches / Weight: 3.26 oz
SPOT BEAM Angle: 7 degrees;Diameter at 3 meters: 360mm
FLOOD BEAM Angle: 60 degrees; Diameter at 3 meters: 3.45 meters
BRIGHTNESS LEVELS Moonlight: 1 lumen, 35 days
Low: 25 lumens, 40 hrs
High:150 lumens, 8 hrs
Max:Burst at 800 lumens, 1 minute
then 400 lumens, 2 hrs
SPECIAL MODES Strobe: 800 lumens at 10hz, 4 hr
SOS: 800 lumens, 4.5 hrs
Beacon High: 800 lumens, 12 hrs
Beacon Low: 150 lumens, 80 hrs
REFLECTOR Smooth highly tuned optical reflector
BODY MATERIAL Type-III hard-anodized aircraft-grade aluminum
BEZEL MATERIAL Stainless steel strike-bezel
Flat black aluminum bezel also included
LENS MATERIAL Optical-grade glass lens, sapphire coating, antireflective coating
INCLUDED ACCESSORIES Holster, 18650 battery (2600mah), USB power adaptor (USA plug), USB cable, lanyard, spare orings, spare rubber boots, flat black bezel, parts for flat tailcap


I continue to be impressed with FourSeven’s commitment to providing good customer service. In addition to the standard spare oring (the wording has actually been changed to plural in the collateral (reflecting that they include more than one with every light I’ve ever bought from them), this light came with spare rubber boots, a flat bezel, and parts to convert the tailcap to a flat cap.

This light is a large departure from the Quark line in many ways, while being relatively small in form factor. Couple this with the fact that the user can reconfigure the light in several ways, and this is quite a versatile light.

Because of its size, I would personally not carry this as an EDC light, though I have a friend who carries a SureFire light that is about the same size (though nowhere near as bright). It has however found a home on my Maxpedition Versipack, and would be super handy in a situation where I needed a lot of light.

For an idea of the size difference between the MMR-X (on the left) and the light I carry daily (on the right), here they are side by side:

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You can see that the MMR-X is substantially larger, but is actually about the original length of the unmodified QT2A light. The head of the light is also substantially larger than the Quark series. Here is another side by side with the MMR-X on the left, and my modified QT2A-X light on the right:

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This is actually a good thing, as the XM-L series emitters that the MMR-X lights use needs a bit larger reflector than the XP-G emitters. This gives the MMR-X a good amount of throw, but make no mistake; the MMR-X is more of a “floody” light, it just also has some pretty good throw. On its highest output, I find that at about 200m the light reaches a point that it does not illuminate the target in a useful manner. At intermediate distances of about 100m though, the MMR-X illuminates the target very well.

One of the key selling points of this light is the incredible 800 lumen maximum output. Yeah, about that.

Let me say up front that I do not have the equipment necessary to test lumens. I believe that the light does put out 800 lumens (and not at the emitter like some manufacturers measure it either). It puts out 800 lumens. For one minute. Then it ramps down to 400 lumens over the next 30 seconds. I don’t know how I feel about that. On the one hand, and let’s be perfectly honest here, if I need 800 lumens, I’m really only going to need it for about 30 seconds, if that. My use case for 800 lumens is as follows:

Oh look, a bad guy! What do I do? I know!

  1. Blind him with 800 lumens to the face! Is he still a threat? Yes?
  2. Burst of three to five, center mass.
  3. Still a threat? No. Don’t need 800 lumens anymore.

Now that’s pretty straight forward. But. On the other hand, what if maybe there is more than one bad guy? What if it’s not clear that I need to shoot them at all, and the light is doing a pretty good job of preventing them from becoming more of a threat/ controlling them? For how long? Is 400 lumens enough?

Don’t get me wrong. If you have ever looked into a 200+ lumen flashlight (guilty), you know that it is not a pleasant experience, and that you are not going to be doing it for very long, and you are definitely not going to be doing anything other than trying really fucking hard not to be looking into the light anymore.

So end result for me is that I really don’t need anything more than a 200 lumen flashlight. Is more better? You betcha. Does it help with illumination at distance? Logic would dictate that it does, so just be aware that you only get that 800 lumens in 1 minute bursts. If that is a limitation that you can accept, great, no problem. Besides, you really shouldn’t be conducting search and rescue ops with a pocket sized flashlight all by your lonesome in any event.

Just be aware that in Strobe, SOS, or Beacon (High) mode, you get the full 800 lumens all the time.

Now, this light offers five distinct operating modes. What does that mean? It means that you can choose how the light functions (and what modes you have available to you), at least you have five different choices.


  1. Max output
  2. Max – Low (this is the default as it comes out of the package)
  3. Max – Strobe
  4. Low – High – Max – Strobe
  5. Moonlight – Low – High – Max – SOS – Strobe – Beacon (high) – Beacon (low)

I feel that (of the five modes offered), the default was a solid choice, and what I keep my light in. I do however take issue with how you have to change the operating mode.

To change the operating mode, the light must be plugged into the USB charger (which is included), and must be using the included “special” 18650 battery. This means that for all intents and purposes, you are stuck with whatever mode you select when you set this up. You can change it, yes. But you’d better be in a place where you have the charger with you. Is that a deal breaker? Not really for me, but I broke this down to several of my friends, and they didn’t like it. Of the five guys I talked to about it, they said they would not purchase this light for that alone. Are they serious? I’ll find out if any of them mysteriously acquire one.

I’ve mentioned before that I like the Quark Tactical interface. I like it in large part because I can select from any of the two operating modes of the light. Personally, I find Max – Moonlight the most useful. If I need a middling amount of light, I have other flashlights, but after over a year of carrying a light daily that was set at MAX – Moonlight, I have yet to need anything in between.

With the MMR-X, once you have the “special” 18650 battery, and the light plugged into the USB charger, you then close the switch on the tailcap, and the light will pulse a number of flashes (between 1 and 5) to indicate the currently selected mode. double clicking the tailcap will advance the operating mode to the next mode. So let’s say that you click the cap once, and it pulses once, pauses for about a second, and then pulses again. That means that the light is in mode 1 (Max). If you then doubleclicked the tailcap, it would advance to mode 2 (Max -Low, the default). Double click it again, and it would advance to mode 3 (Max – Strobe). To select the mode, you either unplug the USB cable, or you turn the light off).

I feel like FourSevens missed a huge opportunity here. If you’re going to require that I have the thing plugged into a USB cable to change the modes, why not just require that I plug it into a computer, and then allow me to configure the operating mode directly using the computer? Like I don’t know, maybe MAX – Moonlight? Or Moonlight – SOS, or… well whatever I want?

This frustrates me, because this is so close to an awesome feature, and then we get all of the pain, and none of the gain. Dammit. Oh well, there is always the next version, or model.

I know you noticed the “special” 18650 battery bit. Ok here is the deal. FourSevens decided to include some sort of modified 18650 cell in this light.

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I don’t know what exactly makes it special, but it is a pretty decent capacity cell, and notice how long it is, definitely longer than other protected 18650 LiPo cells that I have seen (I just happen to have a bunch of the things laying around).

And for $15, it’s not terribly expensive as far as protected 18650 LiPo cells go ($15 isn’t bad). I’m kind of a battery geek (simply because of how much I’ve had ot learn about them to use them safely), and I’m kinda intrigued about this cell. I have a feeling that it is not only protected, but it has some sort of charging circuitry in it as well.

The users manual (which is not very well laid out) does claim that you can run other 18650 cells in the MMR-X, but I’m skeptical simply because the manual states that to do you, you need to remove some plastic piece from the tail cap and insert it into the light before using other 18650 cells in the light. There is no plastic piece that can be unscrewed from the tail cap that I can find.

Then again, this was an advance model for review, so something may have changed and simply not been changed in the manual. In any event, the light did work with all of the other 18650 cells that I tried it with. I tried the light with a variety of 18650 cells, including protected ICR cells, unprotected IMR cells (I don’t know if this is kosher with 47’s, or what kind of safety circuitry is in the light, so you should probably clear that with support before doing it, but it does work), and a couple of unprotected hybrids.

Unfortunately, FourSevens states in the manual that using anything other than the “special” 18650 disables the USB charging capabilities of the light (as well as disabling your ability to change configurations). Due to the nature of LiPo batteries, I didn’t feel the need to burn down my house, or destroy one of my 18650 cells and the light to test that. Again, another missed opportunity.

For me the take away on the whole battery thing is that you are kinda stuck using their “special” 18650 cells if you want to be able to change the modes of the light and use the USB charger. That’s not a terribly big problem because they are warrantied for 12 months, and relatively inexpensive, but something about the loss of functionality unless you use their battery just chaps my ass. It smacks of vendor lock-in, and I hate that.

Not a deal breaker, but not ideal either.

Once of the other major selling points of the MMR-X is that it is user configurable, physically. From the factory, the light ships with a “tactical” style configuration. Momentary on exposed tail switch, and crenelated strike bezel. I’m of mixed feelings when it comes to strike bezels.

Take a look at this bad boy:

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Yeah, that’s gonna leave a mark. Unfortunately, it is also going to leave a mark in a DA’s mind if you ever had to use it, and to a jury you might as well tape a saw blade to the front of your light. I’m just saying that I don’t particularly feel the need to find out what kind of criminal mayhem charge using that thing might bring. Luckily for me, FourSevens was nice enough to include a basic flat bezel in the box, and I switched that out most riki-tik.

They also include parts to change out the tailcap to make it a flat tailcap, which gives the light the ability to tail stand, which is useful if you want to use it to light a room (or for a rave in an abandoned warehouse if you use the strobe mode).

One thing that I do want to touch on is craftsmanship.

Whatever shortcomings this light may have, fit and finish isn’t one of them. Everything fits well, tolerances are tight, knurling lines are crisp (the knurling could be a bit more grippy for my tastes, but that’s a trade off). The USB charging port was an area of concern here. Shouldn’t have been. The connection is tight, the enclosure is well sealed, and the threads on the protective covering are corase, and squared off, so the probability that they will be damaged or degrade over time is very low.

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The red light that you see above indicates that the light is charging, and will turn green once the charging is complete. I do not know if there is cut off circuitry in the light, so you should never leave this light on the charger once charging is complete. LiPo batteries tend to fail in spectacular ways when they over charge, and there is no venting on this light.

Essentially the danger is that when LiPo batteries fail, they tend to do so in a fairly… spectacular manner. It would essentially turn the light into either a grenade or a rocket, depending on what is stronger, the threads on the end cap, or the aluminum body. I’m not saying that failure is likely, but LiPo cells are industrial cells and are not like the alkaline batteries that most consumers are used to dealing with. If you are going to run lights with them, you should do a little bit of research about battery safety and just don’t take any unnecessary risks with them.

Over all, the light is well made, and it does exactly what FourSevens says it does.


Maelstrom MMR-X Regen
POWER SOURCE: ICR 18650 cell (x1)
10 year manufacturer’s warranty on everything that comes in the package (except batteries, the 18650 has a 12 month warranty)
A good performing flashlight, I just can’t help but see missed opportunities when I look at this light.