Noctigon K1 SBT90 Review – Better than Convoy 4X18A SBT?


The Boring Stuff

Reddit user calmlikea3omb kindly lent me this light for a honest review! Here is the official product page and below are the official specs.

What comes in the box?

This light was lent to me without a box, so this section is kind of empty. I do know that it includes a belt holster and that a battery is not included.

Size & Measurements

From left to right:
Emisar D4V2
Fireflies E07x Pro
Noctigon K1
Noctigon K9.3
Noctigon KR1
Convoy 4X18A
Noctigon K1 (Again)
Sofirn BLF LT1

MeasurementMeasured (mm)
Bezel Diameter72.3
Switch Diameter13.4
Switch Proudness1.3
Lens Diameter68.8
Lens Thickness2.6
Reflector Hole Diameter15.9
Reflector Outside Diameter64.9
Reflector Height~60
Body Tube Diameter (internal) 21.8
Body Tube Diameter (maximum)31
Body Tube Length84.8
Pocket Cip Slot Width3.3
Pocket Clip Slot Diameter24.5
Tailcap Diameter28.5
Tailcap Length18.0
Driver Diameter~30

Weight without battery: 322g / 11.4oz
Weight with Molicel P42A battery:
388g / 13.7oz

User Interface

Noctigon K1 comes by default with Anduril, but you can request via email that yours be shipped with Anduril 2, and you should. Anduril 2 is the best flashlight user interface available at the time of writing. It’s easy to use for basic operation, but allows a myriad of customization options and extra features. It’s continually being improved too, and I’m thrilled that it’s an option here.

Inclusion of Anduril/Anduril 2 is a huge deal for me. K1’s closest competitor, Convoy 4X18A, has a poorly implemented UI that feels clunky and works differently than most of my other lights. Since I’m already familiar with Anduril 2, having it included on K1 just feels right, and using it is second nature.

It’s far too complex to do a whole UI breakdown, but here are some of my favorite features:

  • Simple basic operation (1 click on/off and hold to change brightness)
  • Shortcut to moonlight
  • Momentary turbo
  • Customizable mode memory
  • Customizable minimum & maximum brightness
  • Customizable smooth or stepped brightness adjustment
  • Battery voltage readout
  • Sunset timer (dims the light over a customizable period of time)

There are a few features that I greatly appreciated on K1 which don’t exist in Convoy 4X18A. The first is a quick way back to medium from turbo. In Anduril, a double click takes you to and from turbo, but on the Convoy I had to slowly cycle back down to medium after turbo. I also greatly appreciated the low moonlight on K1, since 4X18A’s lowest mode is over twenty lumens! It doesn’t allow you to go from moonlight to low mode either, but K1 does and I uses that feature a fair bit.

Modes, Brightness & Throw

Disclaimer: Lumen measurements were taken on a Texas Ace 3.5″ Lumen Tube. A candela measurement was taken at 8 meters with a Digital Illuminance HS1010A (the meter included with the Texas Ace Lumen Tube) on the highest brightness, and other candela figures were calculated relative to that. Runtime tests were performed with the Ceilingbounce app on my smartphone. All of these tests were performed with a fully charged MODEL battery unless otherwise specified.

Level Lumens (@ Turn-On)Candela (@ Turn-On)Throw (meters)
Turbo (150)4100433,0001316
High (120)1550163,695809
Medium (80)60063,366503
Low (40)12012,673225
Moonlight (1)0.13*147

* Moonlight mode was too low for me to measure directly. To get a measurement, I pointed the light right at a lux meter and measured the lux of Moonlight and Low mode. I divided the Moonlight measurement by the Low measurement, and multiplied the result by my Low mode lumens reading (120).

How did I choose those particular modes? Anduril has 150 levels so doing measurements and tests for each mode is virtually impossible. I’ve got this light set up how I like it with 5 levels. Bottom of ramp is level 1. Top of ramp is level 120, which I believe is the maximum regulated level for this driver. I’ve set up the stepped ramp with 4 steps so, with turbo added, I get the 5 modes I like.

Note: I have since bought my own K1 SBT and it does meet the 4500lm output spec. The sample in this review may just be old or have slightly dirty contacts.

Runtime & Currents

Below are runtimes for both K1 SBT and it’s main competitor, Convoy 4X18A SBT. Use the sliders to compare them!

K1 | 4X18A
K1 | 4X18A

Turbo (150): starts out at 4100 lumens (a little under the advertised output of 4500 lumens). It stays in that ballpark for a little over a minute, then starts a 45-second decline to a little under 1500 lumens. From there, it dips slower, down to about 900 lumens over the course of a few minutes. It fluctuates between 900 and 1000 lumens until just after the 1 hour mark, where low voltage stepdowns kick in.

I also ran another turbo test that was fan cooled, with the thermal limit set to 70C, just to see what K1 can do. Low voltage stepdowns kick in after 16 minutes.

High (120): starts out at 1550 lumens and drops slowly to 1100 over the course of about 15 minutes. It stays there until the 45 minute mark, where low voltage stepdowns kick in. Notably, the sustained output is higher on High than it is on Turbo, even under the exact same conditions, which is very strange on a thermally regulated light. I ran these tests twice just to be sure and got the same results both times.

Medium (80): is a perfectly flat 600 lumens until low voltage stepdowns kick in at 2:15.

LVP: Anduril cuts brightness roughly in half every time cell voltage reaches a particular level (my guess is 3V, but I’m not certain). The reduced draw increases the voltage a bit, so it’s a cycle that lasts until the voltage doesn’t jump back up over that threshold anymore. Then it lasts until (officially) 2.7V where it shuts the light off completely. That process takes quite awhile, so you get plenty of emergency power once your battery is low. It also makes it tedious to let tests run until the cell is completely empty, so I didn’t. I did observe LVP turn off the light if I tried to use Turbo when the cell was around 3 volts, so that indicates to me that the LVP does, in fact, work.

Compared to 4X18A: K1 just can’t compare in runtime or sustained output

Current: I’m not equipped to do extreme duration runtime tests or extremely high current measurements. I only measure the currents on low modes and I calculate the estimated runtime of those modes based on the capacity of the Molicel P42A batteries I’m using for testing.

LevelCurrent @ Tailcap (milliamps)Estimated Runtime
Moonlight1.9490 days
Standby (aux high)0.4651 year
Standby (aux low)0.0499.8 years
Standby (aux off)0.03016 years

Just for good measure, I texted the parasitic drain of the charging circuit in the battery tube when it’s disconnected from the head, and I got less than 1 microamp, which is nothing.

Driver & Regulation

K1 SBT uses a Linear+FET driver. I believe the linear portion handles up to 5A based on the measured output at level 120, this graph from this BLF thread, and some room for reflector & optic losses. Levels 1-120 are within the linear portion. From level 121 to level 150, it uses a FET with PWM for brightness adjustment.

Regulation is pretty good. Turbo drops with cell voltage, which makes sense since it’s FET driven at that level. High reaches the exact same maximum output all the way until the cell is effectively empty. Medium and Low are always exactly the same regardless of cell voltage.

Note: All regulation measurements are taken at turn-on so they do not reflect any thermal or low voltage stepdowns that may occur. In this particular case for all 3V measurements I observed heavy stepdowns shortly after turn on on all modes except Turbo. Turbo shut off immediately.

Emitter & Beam

This K1 has a Luminus SBT90.2 emitter. It’s an insane combo of extreme brightness like an XHP70.2, with extreme throw like an XHP35-HI. It’s also a very expensive emitter, which is why it adds fifty dollars to the cost of the light over the cheapest emitter options. I think it’s worth the extra cost.

When bouncing the light around in my white photo booth, I measured CCT at 5500K and RA (CRI) at 65 with my Opple Light Master 3.

K1 | 4X18A
K1 | 4X18A

Outdoors the beam is incredible. The spill is super bright. The beam is narrow, but not too narrow, and it feels like it goes on forever. The hotspot is a little bit narrower & more intense than 4X18A, and the spill from K1 is a lot narrower than 4X18A because the K1 has a much deeper reflector. Even on a perfectly sustainable medium mode, the spill is plenty bright for outdoor navigation and the hotspot throws far enough for most situations. If you do need some extra punch, Turbo is just a quick double tap away.

Moonlight & Tint Comparison from left to right:
Emisar D4V2 | Luminus SST20 4000K
Noctigon KR1 | Osram W1
Noctigon K1 | Luminus SBT90.2
Emisar D4SV2 2-channel | Osram W1’s
Noctigon KR4 2-channel | Nichia 219B 4500K’s

I calculate moonlight here to be 0.13 lumens. It’s impressively and satisfactorily low. The tint isn’t amazing but it’s not too bad. It’s significantly better than the tint on 4X18A SBT with its laughable 22 lumen “moonlight” mode.

Design & Construction

At first glance, K1 looks a little odd with it’s skinny handle and gigantic head. It’s a design that works though, and it keeps it lightweight. There’s no extra bulk anywhere.

Build quality is excellent, as I’ve come to expect from Hank. This cream anodizing color is no longer available, but it looks smooth and even. The threads are square cut, anodized, and appropriately lubed. Even after all the use that the light’s owner has put it through, they’re still in great shape. There are thick, stiff, gold plated springs everywhere too for high current. K1 just feels high quality.


K1 uses an RGB backlit, electronic, side switch. It’s easy to find, tactile, and clicky. I’m a big fan of nice side switches, and this one doesn’t disappoint. The RGB backlighting makes it even better!

Carry & Ergonomics

K1 is fine ergonomically. It’s not amazing but there aren’t any significant issues. It works in a couple different grips: a normal forward grip with your thumb on the button, and a sort of reverse grip where you palm the head of the light and use your index finger to press the button.

Normally a nylon belt holster is included, but I don’t have it so I can’t comment on that. No pocket clip is included, which makes sense. I tried carrying K1 in a jacket pocket but it’s just too big. The only good way to carry this light on you is in a belt holster.

Batteries & Charging

K1 uses an unprotected, flat top, 21700 battery. You can’t buy one with the light from the manufacturer, so you’ll have to buy a battery separately. For the Osram emitter options, a 5000mah cell with a 10A discharge rating will be fine. But for XHP35-HI and SBT90.2 (shown here) you need more current. I’m using a Molicel P42A for my testing. 18650’s will work in a pinch, even unprotected flat tops.

K1 includes one of the best integrated charging solutions I’ve seen. The charging port is built into the threads of the body tube, so it’s sealed against water and dirt by the o-ring. This is a lot more reliable at keeping particulates out than the cheap rubber flap port covers used on most lights with integrated charging. It also has no problem with over-sized USB-C plugs because it’s not set down into some rubber flap cavity.

C-to-C charging and A-to-C charging both work fine. Charging a P42A takes about two and a half hours. During charging, the end of the body tube will glow red. When charging is complete, it will glow green. It’s worth noting that the contacts on the end of the battery tube connect directly to the cell as far as I can tell, so don’t just toss the battery tube in a pocket with your keys, as that will likely cause a short and lead to some dangerous problems.


Here are some lights in the same class and how they compare.

Convoy 4X18A: Similar overall dimensions, similar brightness but slightly less throw and slightly wider beam. Four 18650 batteries (included) instead of one 21700. Higher sustained brightness and dramatically longer runtime. Significantly inferior user interface. ~$50 less expensive.

Convoy L7: Virtually identical brightness, throw, and beam profile. Similar head size, but with more cooling fins. Two 26650 (optionally included) or 26800 batteries instead of one 21700. Dual-switch design with dramatically simpler UI. Longer and heavier with better balance. No integrated charging. ~$50 less expensive.

Wurkkos TS30S: Smaller, lighter, dimmer (on included battery), substantially less throw, same Anduril firmware but no way to update to Anduril 2. Less-fun switch. ~$50 less expensive. Includes aluminum football kicking tee.

This section is not comprehensive. If I didn’t include a particular light here, it doesn’t mean it’s bad or doesn’t deserve to be here. I simply cannot list every possible competitor.


Is K1 better than 4X18A?

Not really. They’re very similar, but I see them as being good for different use cases. 4X18A is a better tool because of its MUCH better sustained output and runtime. It’s a substantially better value too, being $40-60 less depending on whether you get batteries included. K1 is a better toy because of its light weight and fantastic UI. For me, lights are mostly just toys so K1 is better for me. I just adore the user interface, which was my biggest complaint with 4X18A.

K1 is the best single cell thrower I’ve seen yet, full stop. I ordered one for myself and sold my 4X18A while writing this review because I like K1 SBT so much. I highly recommend it.

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