Thrunite TN42 V2 Flashlight Review

Thrunite TN42 V2 Flashlight Review

Thrunite has released the TN42 V2, an updated thrower, which now outputs a massive amount of light! Read on for testing!

Official Specs and Features

Here’s a link to the Thrunite TN42 V2 flashlight product page.


Despite that there are cool white and neutral white listed on the website, I believe only cool white (as seen here) will be available.

There are at least two previous generations of this TN42 flashlight.  I’ve reviewed two of them.  The Thrunite TN42, and the Thrunite TN42C V2.  The naming went a bit squirrely and while the “C” may be labeled “V2” I’m not sure there was a “TN42C V1.”  Anyway, you can forget that version.  The new one is the best.


Including the four 21700 cells seen in this review, the Thrunite TN42 V2 weighs in at $299.95.  Thrunite has an automatic 5% off coupon though, so you can have this for around $275.  Don’t sleep on the fact that four 21700 cells would be costly if separate!

Short Review

Alright, I have always loved the TN42 line.  It’s fantastic.  The build is great, the user interface is great, the output and throw have been great.  Those are all outdated now.  This Luminus SBT90.2 version is an absolute unit.  Throw is over 2km.  Over two kilometers! (well over the rating).  The output hits specifications, and overall this is just a great light.

Long Review

The Big Table

Thrunite TN42 V2
Emitter: Luminus SBT90.2
Price in USD at publication time: $299.95
Cell: 4×21700
Turbo Runtime Graph High Runtime Graph
LVP? Yes with warning
Switch Type: E-Switch
Quiescent Current (mA): 0.07
On-Board Charging? Yes
Charge Port Type: USB-C
Charge Graph
Power off Charge Port with cells: lowest 2 modes
without cels: lowest only
Claimed Lumens (lm) 4848
Measured Lumens (at 30s) 4490 (92.6% of claim)^
Candela per Lumen 222.7
Claimed Throw (m) 1860
Candela (Calculated) in cd (at 30s) 18770lux @ 7.344m = 1012347cd
Throw (Calculated) (m) 2012.3 (108.2% of claim)^
All my Thrunite reviews!

^ Measurement disclaimer:  I am an amateur flashlight reviewer.  I don’t have $10,000 or even $1,000 worth of testing equipment.  I test output and such in PVC tubes!!  Please consider claims within 10% of what I measure to be perfectly reasonable (accurate, even).

What’s Included

what's included Thrunite TN42 V2

  • Thrunite TN42 V2 Flashlight
  • Four (4) 4000mAh 21700 cells
  • Spare o-rings (2)
  • Wall wart (5V USB-C output)
  • Shoulder strap
  • Spare charge port cover (2)
  • Split ring
  • E-Switch cover replacement
  • Manual and papers etc

Package and Manual

The light ships with a lens protector.

Thrunite TN42 V2 lens cover

Thrunite TN42 V2 manual

Build Quality and Disassembly

Let’s talk about the previous generation Thrunite TN42 lights, for just a second.  The original TN42 lights were all masterful throwers.  They’re big lights, they have a big deep reflector, they should throw.  And they did!  For the longest time (well, till even now, really) I considered the whole TN42 line to be the “go-to” for a common thrower recommendation (sure we have LEPs now but come on.)

The previous TN42’s were dedicated throwers.  They (at least my two) have Cree XHP35 HI emitters, and that’s fantastic for a thrower!  But with this new emitter, the Luminus SBT90.2, we can have the best of multiple options.  Absolutely massive output, but still ridiculous throw.  And that’s what we see here.

So regarding the build quality of this versus the old ones:  this one is the same.  It’s as good or better.  Thrunite does not disappoint.  Regarding updates:  these are good updates.  We’ll cover it all more later, but let’s suffice to say here that Thrunite isn’t really sacrificing anything from the TN42 lineage with this light that throws but also “wall of lights.”

There are a couple of notable updates to the Thrunite TN42 V2.  This version is markedly shorter while using longer cells.  This version also loses the knurling that was popular a few years ago.  I like that knurling – in fact, it was quite useful then.  The Thrunite TN42 V2 could use a ring of knurling on the head somewhere.  You’ll feel this way IF you ever swap the cells.  However, you may never even want to do that, since the included charging is good.

The bezel has screen-printed branding.  This is no different from previous generations.

bezel with imprinting

You can see on the body, head-side, there are minimal-depth cooling fins.  This is good since the light draws around 20A on turbo (!!!).

cooling fins

Nothing going on in the tailcap.


The only place to take the light apart is here – the cell holder comes off the head.  These threads are anodized, square-cut, highly lubed, and very smooth.  They’re short too, which is nice.  I don’t usually love screwing down a cell tube while the cells gets twisted around the head contacts (which is why I often prefer cell holders, which then slip into the body).  But there are a couple of things that make it “ok” here (and one that doesn’t).

First, the threads are short.  Second, when the cells get to where they need to go, the body stops.  You don’t have to crank down and tighten and fiddle and worry is it tight enough and all that.  When you get to “tightened” there is no further.  It’s a smooth stop.  All in all this is very good.

What I don’t like is that there is extremely minimal grip to support tightening the body to the head.  And that’s not just on the head side.  The head is nearly completely devoid of grip and is also large.  So gripping it for tightening can be difficult.  (The previous generation had knurling on the head-side that helped with this very thing!).  Next is the body, which has grip but it’s not really “help with tightening” grip.  I am not saying I’d rather have knurling.  The look here is better.  But it’s a tough call on having something that looks good (this one) vs something that works well (the knurling one).  All this is moot though since you’ll literally never have to take the cells out anyway!  Just charge via the USB-C that’s included, and you’re good to go.

short threads Thrunite TN42 V2

Inside the body, you can see each cell has a spring.  On the head end, which we’ve already talked about, is a brass ring which the cell positive contacts screw against.  There’s a plastic ring there too, which will prevent the use of flat tops.

springs and contact

Size and Comps


  • 190.5mm (length) x 105mm x 57mm
  • Weight: 648g (excluding cells)

If the flashlight will headstand, I’ll show it here (usually the third photo).  If the flashlight will tailstand, I’ll show that here, too (usually the fourth photo).

Thrunite TN42 V2 in hand

Thrunite TN42 V2 in hand

Here’s the test light with the venerable Convoy S2+.  Mine’s a custom “baked” edition Nichia 219b triple.  A very nice 18650 light.

And here’s the light beside my custom engraved TorchLAB BOSS 35, an 18350 light.  I reviewed the aluminum version of that light in both 35 and 70 formats.

beside torchlab boss 35

Retention and Carry

The Thrunite TN42 V2 ships with a shoulder strap, which connects in this little hole on the head.

shoulder strap hole shoulder strap hole

It’s not hard to install, but won’t scratch your new flashlight all up while doing it.

The other end of the strap connects to some of these holes on the tailcap.

tailcap lanyard holes

You really have two options here.  You can connect the strap directly, as seen below.

shoulder strap attached

Or you can connect the included split ring through these holes, and then connect the shoulder strap to that.  I’m not sure which is better but I can say I don’t really know why you’d use this split ring.  ¯(ツ)

split ring

shoulder strap in use

The strap is highly adjustable and quite useful.

shoulder strap attached

This shoulder-carry option really makes me wish Thrunite had a neoprene lens cover for the TN42 V2.

Power and Runtime

The other massive update to this V2 of the TN42 is the cells that are used.  This version uses four 21700 cells.  Those cells are included with the purchase.

with included 21700 cells

The Thrunite TN42 V2 can run on standard button top cells.  Owing to the light not using a cell holder, I’d recommend planning to use these cells exactly.

included 21700 cells

These Thrunite branded cells are “customized” cells – that ring around the positive terminal is exposed and is the anode…  However, that aspect of these cells is not utilized in the Thrunite TN42 V2.  Thankfully.

included 21700 cells

The cells sit just above the body when installed.

included 21700 cells installed

How nice they look in there!  I think this is the first 4×21700 cell light I’ve had, and I have absolutely zero complaints.

included 21700 cells installed

Below are a few runtimes.  Output is a staggering 5100 lumens at startup, and after around 1.75 minutes has a big stepdown.  That’s short of the 125 second claim.  After the stepdown, output maintains around 1900 lumens for nearly 3 hours!  Sorry to say my temperature probe got misaligned from around 30 minutes to around 95 minutes, but I think it’s safe to infer what’s going on there.  The initial temperature spike had happened already.

Thrunite TN42 V2 runtime graph

Thrunite TN42 V2 runtime graph

Thrunite TN42 V2 runtime graph

All in all the runtimes look great.  Note that the shutoff voltage is a little low, around 2.5V in all these tests.  At this point the output was extremely low (maybe 20 lumens or so) and you’d certainly notice that. But you should also notice the indicating switch.  It’s blue when power is “ok.”  Red when power is low.  Red flashing when power is very low.

One more thing about power – these cells are parallel, not series.  So the driver is seeing the 4.2V (or 3.7V nominal) that a single cell provides, and yes that means the Thrunite TN42 V2 will run on a single cell.  Now, I wouldn’t push Turbo through a single cell, because that’s quite demanding on a single cell.  But in a pinch, you should be able to get some of the lower modes for some time if you have to.


Unlike previous TN42’s which had charging, the Thrunite TN42 V2 utilizes normal USB-C.  There’s a charge port right here in the head, exactly on the opposite side from the switch.

The charge port cover seems very secure and is in fact a little hard to grab to open.  (That’s the better option than it being too easy to open!)

Thrunite includes a charge adapter.  This is a “wall wart” to USB-C plug.  The output here is 5V, so no power delivery (which makes a little bit of sense since the cells are in parallel, and 4.2V total) (not that they couldn’t have done it with power delivery if they wanted to, but I think that gets more complicated internally).  (That said, PD on this light would be amazing – 20V or 12V at 2A or whatever, would certainly charge the light faster!)

wall wart


This cable is built into the wall wart (unfortunately).  Seems like Thrunite could have provided a wall wart that had a USB-C plug and a C to C cable.  On the other hand, this definitively limits the charge voltage to 5V, and should prevent a user from grabbing some other plug (like the Olight Marauder II, which is PD and can output higher voltages.)

wall wart

Charging is good, and a respectable 5ish hours for the 16000mAh battery (remember, these four cells are parallel.  So capacity is cumulative, not voltage).  (Just to finish the thought – if they were series, the voltage would add and the capacity would be just whatever one cell was listed as).

Charging peaks at around 3A, which is perfectly fine for four 4000mAh cells getting one-fourth of 3A.  That’s slow, even, but such is the nature of 5V USB output.

USB-c charging

Modes and Currents

Mode Mode Claimed Output (lm) Claimed Runtime Measured Lumens Tailcap Amps
Turbo 4848/1737 125s/160m 4490 17.59 (++)
High 1863 3h 1959 5.90
Medium 425 15h 479 1.00
Low 80 82h 124 0.23
Firefly 1 180d 0.82 3.52mA

Pulse Width Modulation

No PWM is seen.

For reference, here’s a baseline shot, with all the room lights off and almost nothing hitting the sensor.  Also, here’s the light with the worst PWM I could find.  I’m adding multiple timescales, so it’ll be easier to compare to the test light.  Unfortunately, the PWM on this light is so bad that it doesn’t even work with my normal scale, with is 50 microseconds (50us).  10ms5ms2ms1ms0.5ms0.2ms.  In a display faster than 0.2ms or so, the on/off cycle is more than one screen, so it’d just (very incorrectly) look like a flat line.  I wrote more about this Ultrafire WF-602C flashlight and explained a little about PWM too.

User Interface and Operation

There’s a single switch on the Thrunite TN42 V2.  It’s just below the head and is a clicky e-switch with an indication function.  It’s exactly like the TN42 switch (which I also loved).

I like this switch.  The action is low, the pad is wide, it’s metal (or close enough), it’s easy to find…. Thrunite does e-switches right!


The blue is a bit washed out here, but it’s a nice blue (not such a “white” blue).  The switch can also indicate in red.

e-switch indicating

Here’s a UI table!  The user interface is unchanged from previous lights.

State Action Result
Off Hold Firefly
Off Click On (Mode Memory except for Turbo/Firefly/Strobe)
Any Double click Turbo
Turbo Double click Strobe
On Hold Mode cycle (LMH)^

^ There’s a mode cycle that’s hard to explain in table form. When the light is on, the only way to get to High is to cycle from low. If you turn the light on to Medium and hold the switch to advance, the advance is to Low first, then Medium then High.  In fact, any time you’re in medium, and you release the switch, the next advance upon holding the switch, will be low, whereby you need to cycle through low and medium to get to high.  I found this to be quite cumbersome.

LED and Beam

Thrunite went with a Luminus SBT90.2 emitter for the TN42 V2.


like this emitter.  It’s a weird combination of output and throw that seems like we’ve jumped into some new era of emitter technology.

shaped bezel

That said, it’s not quite as “clean” of a thrower as the previous – those smaller Cree XHP35 HI emitters had a tighter hotspot and less spill than this light has.  That’s a choice you’ll have to make based on your needs, but I can say, this light is fantastic!

uncalibrated beamshots

These beamshots are always with the following settings:  f8, ISO100, 0.3s shutter, and manual 5000K exposure.

Tint vs BLF-348 ( 219b version) (affiliate link)

I keep the test flashlight on the left, and the BLF-348 reference flashlight on the right.

I compare everything to the 219b BLF-348 because it’s inexpensive and has the best tint!


What I like

  • Massive output
  • Stunning throw
  • Cells are included
  • Included cells are very high quality
  • Regular USB-C Charging
  • Uses 21700 cells
  • Good user interface

What I don’t like

  • Charging is at 5V, instead of higher voltage power delivery
  • Price is $300
  • Cool white only


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6 thoughts on “Thrunite TN42 V2 Flashlight Review”

    1. Ooh that’s tough right there. The K75 has a handle, which might be enough to push you over to it. It’s more of a thrower too, which might make it more appealing (if you need a thrower).

      All other things being equal (that is, if you don’t need a thrower or need a handle, then I’d probably say I’d rather have the Thrunite. I prefer the smooth anodizing and feel of the Thrunite. Also, it uses a larger cell size (and they’re included), which is appealing.

      The Thrunite is probably available for less money, too. That’s a very important point of comparison between the two…

    2. Whitney J. Broussard II

      I have both. The K75 throws further but alot bigger and not practical to carry around. The TN42 V2 is perfect size and power. And much more portable and praticl and still a beast.

  1. Thank you very much for the explanation and your time! You’ve made a great point re: cost.

    Looks like one might be able to find the Acebeam for just north of $200 (w/o batteries) and the Thrunite for less than that – but like you say, it’s got the batteries and charger included. Choices, choices.

    I’ve got a quick additional question, if you don’t mind.

    I see the Acebeam K65GT on your “Arbitrary list of popular lights – Summer Solstice 2021 edition” but am having trouble finding much additional information about it. How familiar are you with that light? Are you a fan of it? If so, would you rather have that or K75/TN42V2?

    I realize it’s more of a hybrid, but I am looking for a light to complement and/or replace a T27 and an old K70. And, on paper at least, the K65GT seems like it might offer some of that in a smaller format than the K75 (that was how I was trending before given my lack of personal experience with Thrunite — which raises a whole other but related question, which brand do you currently prefer between the two?).

    Thanks again for your help here and your thorough and informative reviews.

    Best regards,

    1. I’ve never held a K65GT. Honestly, that seems like more of a competitor to the TN42 V2 than the K75 does (despite the K65GT not throwing quite as far).

      Between the three, it’s probably just down to cost for me. Throw on paper is different but in practice, I wonder if you’d notice much difference at >1.5km (probably not).

      Next, it’s battery comfort level. If you are already set up for 18650, you might not wish to move to 21700 cells (even if they will always live inside the flashlight.) So that’s a consideration.

      Preference between these two brands? None really. I think these are two of the top flashlight brands available today. I would comfortably go with either of these brands over nearly any other, especially in a light like the format you’re chasing. I probably like the feel of Thrunites more because I like the non-matte anodizing. But this isn’t a performance characteristic. On the flip side, the Acebeams will have more grip due to their finish and knurling.

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