Emisar KC1 (519A 5700k dedome) review

Published 2023/11/19

Updated 2023/11/19

Categories: Review, Emisar, Keychain lights, 10440 lights, Dual chemistry lights,

Table of Contents


"...so, I guess I'm starting small?"

"Can a keychain light be a hotrod? Let's find out..."

The Emisar KC1 is a 10440/NiMH AAA keychain light with excellent performance for its size.


Introduction, Background, and Official Specs

The Emisar KC1 was announced on November 13 2023 by jlhawaii808. The KC1 was subsequently released on intl-outdoor.com on the 22 Nov 2023. At the time of writing (22 Nov 2023), the KC1 is priced at $12.99 from Hank, and $17.88 from jlhawaii808.

Hank Wang of intl-outdoor.com is best known for making enthusiast-oriented lights with anduril and a lean towards high output, so the KC1 is something of a departure from his usual lights, being a single-mode dual-chemistry twisty keychain light.

All of jlhawaii808's stock came by default with a 519A 5700k dedome. Directly from Hank, the emitter choices are:

Official specs:

Parameter Value
Length 67mm (2.65 in)
Head Diameter 14.8mm (0.58 in)
Body Diameter 13.5mm (0.53 in)
Weight (no battery) 12.3g (0.43 oz)
Weight (with 10440 battery) 22g (0.77)

Emitter options are as follows (prices from Hank):

Emitter CCT Price
SST20 6500k, 5000k -
SST20 95CRI 4000k, 2700k -
519A dedomed 5700k, 5000k, 4500k, 3500k, 2700k $1.99
219B 4500k, 2700k $1.99
SST20 Deep Red 660nm red $1.99
W1 6000k $1.99

Other emitter options are usually available by email request to Hank with most of his lights. It has been specifically mentioned that domed 519A do not fit the optic, which would also imply LH351D would not either.

After purchasing, jlhawaii emailed me, saying that the light gets very hot and offered to swap a resistor to a higher value one to reduce the output. I did not take this offer. It currently remains to be seen whether Hank will offer this as an option or not, but it's worth considering. As it is, this review related to the more hotrod version, but note that a lower output version is also possible.

I purchased this light with my own money directly from jlhawaii808. I am not being compensated for this review and do not have any kind of referral or affiliate agreement with any sellers.

First impressions

The light comes in the standard Hanklight box most readers will probably be familiar with, although in the case of this specific light, it came without the typical label that Hank uses on his boxes. Two spare o-rings and a split ring are included.

Physical design and build quality

The KC1 shares many elements of the Emisar design language, with the knurling found on the tailcaps of many Emisar/Noctigon lights being present on both the head and tailcap here, although with a smooth body tube rather than the typical square pattern found on most. There are no cooling fins, although the usual grooves on the battery tube are present, despite no pocket clip being included or available optionally. The head is made of thick aluminium, with a single TIR optic (the same optic as used in the Noctigon DM1.12 flood channel). On the tailcap, there is a relatively large loop for a lanyard (not included) or split ring. This loop is relatively narrow, and combined with the light's mass, particularly in the head, makes it very difficult to tailstand (it is possible to, but takes some time/effort and a decent sense of balance. I mostly made it tailstand by placing it against another object for support then removing that object. Given the intended use case of this light, this really isn't one you will be using to ceiling bounce a room, so this is not a big problem, especially if you are attaching it to a set of keys. The anodisation looks and feels very high quality, and under intense lighting almost has a slight sparkle to it.

The only thing that in my opinion qualifies as a design flaw is in the head - with a battery inserted, when the head is tightened down to the maximum it can be without the light being switched on, the o-ring is slightly exposed. If you are going to pocket carry this light, given how hot it is able to get, you will probably want to untwist the head an additional half turn or so from this point, at which point the o-ring is clearly visible. Not a huge problem as the o-ring on a twisty light is likely to get chewed up over time anyway, and replacements would be cheap and easy to find, but something to be aware of. This could be solved relatively easily in a new revision by making the overlapping part of the head 1-2mm longer. When inserting a battery, the light does briefly light up when the head first makes contact with the tube, but this only lasts a very short time before you start tightening it. If anything, it reminds me of the power-on blink that Anduril has, although I feel this is an unintentional effect overall. When there is not a battery in it, the tailspring rattles slightly when shaken, but this does not happen with a battery inserted, even when the head is untwisted to an off position.

Size comparison

From left to right, featured lights:

User Interface

State Action Effect
On Untwist head Off
Off Tighten head On

This is a twisty light. Put the battery in, tighten the head, lumens come out of the end. Loosen the head again to switch it off. UIs don't get simpler than that.

Driver and emitters

The driver is a dual chemistry linear/boost driver with a single mode. When using a 10440 battery, it uses a 2A unregulated driver, and when using a AAA battery, it uses a boost driver (of unknown current).

The LED in my example here is a dedomed 5700k 519A, which comes out to approximately 4000k with a balanced to throwy beam profile, which is slightly offset by the small optic which makes the beam floodier. This was the default LED option for the first batch sold by jlhawaii; Hank offers more LED options as described in Introduction, Background, and Official Specs. In particular, dedomed 519A lose a fair amount of output over domed, so I am interested in in the future testing a KC1 with W1 or SST20, which should have both higher output and more throw.

Opple measurements:

Subjectively, the light has a very nice beam. The beam is perfectly round with no artifacts. DUV is negative. Here is a comparison of the KC1 (right) with my Skilhunt E3A (left):

Updated December 2023: Took some proper spectrometer readings.

Power and charging

The KC1 takes either a li-ion 10440 battery, or a 1.5V AAA battery. There is no built-in charging. Given the pwoer of this light it will rapidly drain its battery, so if using 1.5V batteries, I would recommend white label Eneloops over Eneloop Pro or alkalines.


The driver is extremely small, so removing it may be difficult. The head is a single piece with no separate bezel, so the entire head internals would come out through the back where the driver is. The actual construction of the head is relatively simple, so emitter swaps are likely possible. The body tube and tailcap appear to be a single piece, and the tailspring is just friction fit inside.

Do you have teardown photos? Email me or DM on BLF or Reddit if you are interested in me using them (with credit given).


Now to what matters: It's powerful. Impressively powerful. Hank is well known for building enthusiast-oriented "hotrods", and a few people on Reddit were very critical of this product announcement, calling it a cash grab or evidence of Hank having jumped the shark. In my opinion, this couldn't be further from the truth. While obviously, I wasn't expecting enormous output or excellent runtime, the output is extremely impressive for such a small and low-powered battery.

The output of the KC1 even with a dedomed 519A is comparable to the kind of 2-3 AA light nonenthusiasts often use, although obviously without the same runtime. With an SST20 or W1, it is likely to be noticeably brighter. Of course, all this power comes at a cost - this light gets very hot. I have more heat-resistant hands than most, but after a minute of use with a 10440, it was definitely uncomfortable to hold. If heat might be a problem for you, I would recommend the resistor swap, but if like me, you want as many lumens as possible, this light is unbelievably fun in its hotter configuration. When I was doing the longer runtime tests with 10440, it became way too hot to hold to the point that even removing the light from the holder after 10 minutes was painful to my fingers. Within normal in-hand use, it started to become hot to the touch after a minute and uncomfortably hot after 90 seconds.

On the runtime test, after 9 minutes, it started flickering rapidly; I noticed a high of >300lm and a low of ~100. I am not sure of the possible cause of this, but as the light was almost too hot to touch, it could be the performance of either the battery or driver suffering. I paused the test and took the battery out and it was at 3.3V, so I continued the test (at this point the light was still hot enough to be difficult to touch) and the flickering did not reappear, and output continued to gradually drop, reaching zero. Neither the light nor the battery appear to have been damaged and both still work fine. If you are using the KC1 in a real world situation rather than doing runtime tests, this is extremely unlikely to happen to you as the light had been too hot to hold for several minutes at this point.

Wiith Eneloops, it's much more manageable thermally, not getting more than very slightly warm to the touch, and managing a runtime of almost 40 minutes. While it's not as fun as with a 10440, if you're actually looking to keep one on keys or another similar object and use it for practical purposes, an eneloop might be the better choice than 10440 (although personally, I'll probably be using mine with a 10440 as a tiny memeblaster).

To give a basis of data for comparison, I tested several other small lights in my collection that use either a 10440 or are 10440/AAA dual-chemistry as well.

The Emisar KC1 does not have LVP, so in the extended runtime test with 10440 batteries, I stopped to check battery voltage, but if you are considering this light then you already know it's for a short burst of as much light as possible from something so tiny, and not intended for sustained use.

All lumen measurements taken using a 4.5 inch Texas Ace lumen tube. I did not have an adapter ring small enough for any of the tested lights, so some light will have escaped, so these measurements likely tend slightly lower than realistic. Candela measurements were performed indoors (0 ambient lux reading on the luxmeter) at a distance of 3m, using a UNI-T UT383BT.

Runtime tests were performed using the lumen tube's HS1010A luxmeter, which the tube is calibrated for, with data recorded via taking a video, exporting the individual frames using ffmpeg, and parsing the value on the luxmeter's display at the appropriate frame for each measurement. I chose a 15 second interval as this methodology is still currently not perfect.

10440 battery

Light Peak output Output after 30s Output after 1 minute Output after 90s Output after 5 minutes Peak candela
Emisar KC1 (519A 5700k dedome) 464 lm 404 lm 390 lm 387 lm 348 lm 3,501 cd (118m FL1)
Lumintop Frog (v2, with the worse UI) 432 lm 3,267 cd
Lumintop GT Nano Pro (v2, with the worse UI) 980 lm 7,146 cd
Lumintop GT Nano (v1, with Narsil) 712 lm 30,033 cd

Eneloop Pro AAA

Light Peak output
Emisar KC1 (519A 5700k dedome) 114 lm
Skilhunt E3A 107 lm

Eneloop (white wrap) AAA

Light Peak output Output after 30s Output after 1 minute Output after 90s Output after 5 minutes Overall Runtime Peak candela
Emisar KC1 (519A 5700k dedome) 120 lm 115 lm 113 lm 111 lm 107 lm 39m 45s * 711 cd
Skilhunt E3A 107 lm 106 lm 106 lm 106 lm 105 59m 45s 693 cd

There was no difference between the Eneloop Pro and non-Pro detectable to either my lumen tube and luxmeter, or to my eyes, so the boost component of both of these lights is drawing less current than even a standard Eneloop is capable of providing, so I did not bother to test extensively with the Eneloop Pro as for this reason there is little reason to use one over the standard Eneloop, as they are more expensive and have a lower capacity and cycle life (plus I own fewer of them to test with).



The Skilhunt E3A is a comparably sized AAA light with a single mode twisty UI. Compared to the E3A, the KC1 is somewhat more powerful, but has a shorter runtime, and the E3A does have better regulation, translating to a lower output but higher runtime. Build quality is largely comparable, while I would give the KC1 the win on aesthetics. On the other hand, the KC1 easily wins in quality of the light produced, with much less green tint, and slightly higher candela.

Of the other lights I tested against in this review, the Lumintop Frog is similar in output (although with a much less nice LED), but is more of a "proper" light with a full UI, that can be switched off with the head fully tightened down (although it has a switch LED which will drain even a 10440 over a relatively short time). The Lumintop GT Nano and GT Nano Pro are both larger and higher output and included more as a comparison datapoint than as something you would be likely to be cross-shopping with a KC1, and none of the Lumintop lights mentioned here support Eneloops, only li-ions.

Final thoughts and score

The KC1 caused some controversy on /r/flashlight and /r/hanklights when it was announced, but in my opinion, this is a Hanklight through and through. I don't have a lot of use for a keychain light and it certainly won't be displacing my D4K as my EDC, but it certainly has the classic Hanklight wow factor, and as much as I would have rather seen a 10440 sized anduril light more along the lines of the Frog or GT Nano, it is excellent for what it is, and with a brighter LED than a dedomed 519A, this might be a top tier lumens per gram, and for the size it has incredible wow factor. When it becomes available on int-outdoor.com I am likely going to pick one up with W1 and/or SST20 for a higher output. With an Eneloop, it's nothing specifically outstanding in performance and there are more similar lights available, but in my opinion, it far surpasses those in terms of looks and build quality, as well as in choice of LEDs. It is also worth nting that the KC1 is an excellent way to push a small order from Hank over the $40 free shipping threshold, as the shipping fee for orders below $40 is $8, essentially making the KC1 have an effective cost of $5 when used as an addon to an order to qualify for free shipping.

Category Score Comments
Looks 8/10 There's not a lot of ways to make a keychain light with unique physical design, but Hank has made the KC1 look consistent with the rest of his lineup. It definitely looks like it belongs.
Quality 8/10 There is a slight rattle from the tailspring when shaken when there is not a battery inserted, but I own several other keychain lights that do the same thing. The anodisation and milling is excellent quality, and the optic and LED seem well seated.
User interface 5/10 It's a twisty. Not a lot to say here. It works, as long as all you want is on/off.
Performance (absolute) 9/10 For a keychain light, this is amazing performance, on par with some "proper" 10440 lights
Performance (sustained) 6/10 On a 10440, it had some issues, but at this point the light was already way too hot to hold. On an Eneloop, the regulation isn't perfect, but 35 minutes of usable light is still very good.
Moddability ??/10 The head is less complex than the Emisar D2, and hopefully someone will try, but at the moment I have no data to go on
Practicality 8/10 For close to 500 lumens for a short time or for 30 minutes of usable light in only 22g, this is the perfect light for the kind of person who finds even a 14500 light a burden. Chances are you are carrying more weight on your keyring just in keys
Value 7/10 It's priced slightly above some comparable lights, but it's a Hanklight, and you definitely get your money's worth in performance and quality
Fun 8/10 For the size and weight, I can't think of anything comparable. There are more fun 10440 lights, but they are all significantly larger (e.g. GT Nano)
Overall 8/10 In my opinion, this is a worthy addition to the Hanklight family. Mine won't be going on my keys, but it will definitely be getting some use to impress people

The Emisar KC1 can be purchased from jlhawaii808. As this is a Hanklight, it will be available directly from Hank at intl-outdoor, although has not been listed at the time of writing.

This is my first proper review on my own site (although I have written various shorter-form and forum-based reviews before) and this took a lot of effort for me and is definitely a passion project ( as well as a way to go from "enby with lots of lights" to "actual light reviewer" ;) ), and I would appreciate any feedback. I am active on BLF or Reddit, both on /r/flashlight and other specific subreddits, and have started my own subreddit for review content at /r/WolfgirlReviews.

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