Lumintop GT Nano Brass 10440 Flashlight Review

Lumintop GT Nano Brass 10440 Flashlight Review

The Lumintop GT Nano Brass flashlight is out…. and it’s been out for a while, and I’ve reviewed it, but now I have the 10440 body!  I was excited about it from the start, and it’s just as fun as you think it should be.  Read on for some thoughts and testing!

Lumintop GT Nano Brass 10440 Flashlight Official Specs and Features

Here’s a referral link to the product page.


Of course, there’s the aluminum version – I reviewed it already.  There’s brass (seen here) and copper.  Lately, there is titanium, which is available in three finishes.  These all have the same emitter.

What you’re seeing here is the 10440 body of the Lumintop GT Nano Brass flashlight.  Yes, I reviewed the 10180 body before.  But I ended up with this 10440 body from Neal (sort of accidentally) and told my good friend Neal, “hey why don’t I just review it too?”  So here we go!


These range from $4.95 (aluminum) to $10.95 (copper).  The brass as seen here is $9.95.

Short Review of the Lumintop GT Nano Brass 10440 Flashlight

I already loved the aluminum GT Nano.  But I love brass more, so what’s better than a brass GT Nano?  And what’s better than the short 10180 cell runtimes?  Longer 10440 runtimes, of course!

Long Review

The Big Table

Lumintop GT Nano Brass 10440 Flashlight
Emitter: Osram CSLNM1.TG Flat White (1mm)
Price in USD at publication time: $9.95
Cell: 1×10440
Turbo Runtime Graph High Runtime Graph
LVP? Warning
Switch Type: E-Switch
Quiescent Current (mA): 0.24 (with indicating switch on)
0.02 (with indicating switch off)
On-Board Charging? Yes
Charge Port Type: micro-USB
Charge Graph
Power off Charge Port
Claimed Lumens (lm) 450
Measured Lumens (at 30s) 417 (92.7% of claim)^
Candela per Lumen 67
Claimed Throw (m) 300
Candela (Calculated) in cd (at 30s) 694lux @ 5.957m = 24627cd
Throw (Calculated) (m) 313.9 (104.6% of claim)^
All my Lumintop 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

Since the light itself is a separate purchase, what’s included is simply:

  • Lumintop GT Nano Brass 10440 cell tube

Package and Manual


The cell tube ships sealed.  Here’s the manual for the light itself:


Build Quality and Disassembly

feature photo

The Lumintop GT Nano Brass has the look of all the other GT series light, it’s just made of brass! So it’s perfect in this regard.

The 10440 body adds a bit of length that gives the Luminus GT Nano Brass 10440 much better in-hand usage.

Here’s the top-down view!

Those little fins on the head for cooling are super narrow!  You can see it later but this is a very slight design change from the aluminum version.

head removed

The tail end has a spring, while the head end has only a brass button for contact.

internal contacts tailcap


both bodies 10440 body

Size and Comps

10440 body alone: 25g
Head: 33g
Dimensions:  24 x 79mm

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).

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

Here’s the 10440 body (in brass) vs the 10180 body (in aluminum).  Quite a difference!  That difference makes the longer body so much more manageable, too.

both sizes

This brass Lumintop uses ages very nicely.

lumintop brass

Retention and Carry

There is just a lanyard hole on the GT Nano.  With just the 10440, a lanyard is not included.  The GT Nano light itself will include a lanyard.  Also, it’ll include a split ring and hook, which is nice.

Power and Runtime

The Lumintop GT Nano is powered by a single lithium-ion cell.  What ships and is intended for the light is a single 10180 cell – a tiny cell!  These are rated at 80mAh capacity, which is a tiny capacity.

This review is of the long body, of course, and so the power for this test is a 10440 cell.  The 10440 cell I tested with is a 350mAh cell.

both bodies and cells

The 10180 fits into the GT Nano in the usual way – positive (button) end toward the head.

10440 installed 10440 installed

Here are a few runtimes.  The output on this light is quite fantastic (even disregarding just the actual throw of it).  You’ll note a couple of stepdowns in the runtimes – the light flashes a few times at every step down.

runtime graph

I reset the light to “High” a couple of times just to see what would happen.  I find it to be interesting, especially since at that point the light had already stepped way down.

runtime graph runtime graph


The GT Nano also has a charge adapter.  Lumintop includes a cable – USB to micro-USB.  It’s a very short cable.

The little plastic bit seen below just unscrews – I suppose it’s just there for protection.

charge head

Also included is a “charge head.”  It’s brass and has some plastic bits for protection.  The plastic dome on the top (below) actually has charge indicators, too.  Red for charging, and green for charging complete.

charge head with body

Here’s how the charging head fits the GT Nano.  It of course can’t be used while the flashlight head is installed.  It works on the 10440 body just fine.

charge head on body

Charging is a reasonable 0.1A or around 1C.  I’m not really sure what’s going on with 10440 charging.  It seems like one test stops early, and one stops way late (at 4.23V).  Neither of these is particularly good (though 4.19V is much more acceptable than 4.23V).

charge graph

Modes and Currents

Mode Mode Claimed Output (lm) Claimed Runtime Measured Lumens Tailcap Amps
Turbo 450 (100%) 417 >6A
4 40% 283 1.80
3 15% 127 0.33
2 1.5% 10 0.02
Moonlight 0.5 ~0

Pulse Width Modulation

Narsil has PWM on moonlight (left) and 2 other intermediate modes.  Turbo doesn’t have PWM though, and the 15% doesn’t either.  I don’t notice the PWM on any mode, however.

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

The user interface is a single side clicky.  An e-switch, with a red indicator.  The switch looks huge on this tiny light, but overall it’s still not a huge switch.


It’s also very domed and has a sort of “squishy clicky” action.  While I could not always count on a click to do what I expected, it did seem to be better than the “appx 70% reliability” I found for the aluminum version.  (This did not diminish my opinion of the light, though, even if it should have.  It’s just too much fun.)

The UI is exactly as on the other GT lights.  This will be a copy-paste of that UI.  I also always set these lights to stepped for testing, since it gives specific modes for testing.  But ramping is all the rage, and I like it fine too, so it’s nice to be able to switch between the two.

The UI itself is a version of Narsil, by Tom E.  The version my light shows is Narsil 1.3.  (Check this by clicking 3x, then 2x, then 2x, and the version will be blinked.  1 blink, pause 3 blinks.)

The UI is much too complex for my usual table, and I’m not going to undertake that here.  This Cheat Sheet is not my work! but is very useful, and thorough.

lumintop gt nano osram 10180 thrower narsil cheat sheet

There are two groups.  One group has ramping, one group has discrete modes.  It’s possible to switch between ramping and discrete easily.  The default is ramping, and to switch to modes, first turn on the light, then hold the switch for 3.2s.  It’ll blink twice, pause, and blink once.  At that point, click once.  This disables ramping.  Once this is done, put the light down so you don’t change other settings (which is very easy to do.)  There are other things you could do to expedite termination of programming, but just skip it, and wait.

Due to the very high standby drain that the switch LED has (0.24mA), I recommend that you disable the switch led.  You can see how to do it in the cheat sheet above, but let me tell you what clicks to do here, too.  I recommend starting in ramping (but you don’t have to) (see the previous paragraph on how to switch between stepped and ramping).

  1. Turn the light off.
  2. Access battery check mode by clicking once then click and hold for >1.1s.  (The light will turn on low, then go to high, then begin blinking out the battery voltage).
  3. During the voltage blink out, click and hold the switch for >1.1s.

You have now entered the secondary LED/switch LED configuration menu.

  • The light blinks twice quickly, then once quickly.  Clicking once disables the locator LED feature.  Clicking twice enables it (this is the default, too).
  • The light blinks twice quickly, then twice quickly.  Clicking once disables the battery level indicator LED (this is the default).  Clicking twice enables it.
  • The light blinks twice quickly, then thrice quickly.  Clicking once disables the Indicator LED.  Clicking twice enables the Indicator LED (this is the default.)

After this, the light will blink 4x very quickly and exit programming.

Narsil is wonderful firmware.  It’s extremely versatile, and possible to change many (most? all?) of the settings about the light.

LED and Beam

The beam selected for this Nano thrower is an Osram Flat White emitter.  Really the perfect choice.  It’s specifically a CSLNM1.TG, the 1mm version of Flat White.  This means it’s cooler (maybe 6500K), but also the emitting surface is smaller (1mm squared) so the throw is excellent.


The reflector is smooth and deep.

smooth reflector emitter on taking off like a rocket ship

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!

Conclusion about the Lumintop GT Nano Brass 10440 Flashlight

What I like

  • No brass light that is more fun for fewer dollars
  • Performance (output) is excellent
  • The “to scale” vs other GT’s is incredibly well done

What I don’t like

  • Switch on my copy is a little unreliable
  • Output on Turbo claimed at 2.5A, but in fact, seems unregulated
  • Switch indicator is red on mine at all times (even with freshly charged cell)
  • Parasitic drain is massively high with the indicator on (but just turn it off, and everything is fine)


  • This light was provided by for review. I was not paid to write this review.
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