The Boring Stuff

Wurkkos sent me this light in exchange for a honest review. Here is the official produce page, but you can also buy it on Amazon. It usually hovers between $15 and $20 but I’ve seen it as low as $10! Below are the official specs, and output numbers are presumable for the higher efficiency and lower CRI cool white version.

What comes in the box?

The box is the typical Wurkkos box: white & yellow cardboard with Wurkkos’ logo on top. Inside you’ll find the light itself wrapped in a bubblewrap sleeve, a manual, and two spare O-rings. Notably, no batteries are included.

Size & Measurements

From left to right:
Sofirn SC21
Olight i3E
Sofirn C01S
Wurkkos WK02
Thrunite Ti4
Xtar T2

Measurement	Measured (mm)
Bezel Diameter	14.0
Length	128.6
Switch Diameter	8.5
Switch Proudness	3.9
Body Tube Diameter (internal)	10.6
Body Tube Diameter (maximum)	14.0
Pocket Clip Space (for pants material)	2.5
Pocket Clip Width	5.5
Pocket Clip Thickness	0.6
Pocket Cip Slot Width	4.2
Pocket Clip Slot Diameter	12.3
Tailcap Diameter	14.0
Tailcap Length	8.3
Driver Diameter	11.0

Weight: 44g/ 1.6oz with Eneloops, 20g / 0.7oz empty

User Interface

This UI is perfect. There are three modes and it always starts on low. No mode memory, no strobes, no nonsense. Since there’s no mode memory and a forward clicky switch, I can get to exactly the mode I want, from off, without fully clicking the light on, even without looking, in an instant. I love it, and I wouldn’t change a thing.

Modes, Brightness & Throw

Disclaimer: The lumen numbers in these next three sections are only estimates. I don’t have the equipment to do lumen testing, so I’m assuming the high output here is 210 lumens (300 is probably for 6500K: 4000K SST20’s are 70% as bright as 6500K: 70% of 300 is 210) and I calculate all other lumen numbers relative to that. All measurements were taken using the Ceilingbounce app on my smartphone. All of these tests were performed with fully charged white eneloop AAA’s unless otherwise specified.

Level	Lumens (Estimated)	Current at Tailcap (miliamps)	Candela	Throw (meters)
High	210	too high to measure	1250	71
Medium	45	195	268	33
Low	1	18.4	6	5

Runtime & Currents

High (with Alkaline AAA’s): On regular generic AAA’s, WK02 starts at at what I’m assuming is 210 lumens and drops slowly to ~150 lumens over the course of 15 minutes. Next there’s a hard drop to low mode and it stays there until the 3 hour mark. At the 3 hour mark, I re-activated high mode just to see how it would cope. It jumped up to a little less than 75 lumens and stayed above 50 lumens for about five minutes before another hard drop to about 10 lumens. Then it slowly dwindled for the next hour to nearly off, then picked back up a little bit to low mode again. It stayed there until I ended the test at a little over 8 hours. At that point the cells were at 1.2 volts, which is effectively empty for alkalines. I did not observe it ever actually turn off though.

High (with NiMH AAA’s): Eneloop AAA’s dramatically outperform alkalines here. They sustain a higher output (just under 200 lumens) and last precisely as long as is advertised: 35 minutes. Then there is a dramatic drop in output and I shut off the light as not to over-discharge my cells. It’s clear that whatever regulation circuitry Wurkkos has included works much better with NiMH cells than Alkaline cells. During this test the head got a little too hot to hold comfortably, but not hot enough to cause concern about the electronics. The body got warm but did not get hot. ~200 lumens sustained output is very impressive from such a small head on such a small light with a high CRI emitter. I hardly get that sustained output from a much more massive Emisar D4V2 with these same emitters!

Medium: On Eneloop AAA’s medium starts out at 45 lumens and drops to 35 lumens over the course of a few minutes. It stays there with a couple of minor fluctiations until just before the four and a half hour mark. Then, there’s a sharp drop in output just like on High mode, and I ended the test. I did try re-activating both Medium and High, but they just flashed a little brighter than low for an instant then dropped to low.

Emitter & Beam

WK02 uses a Luminus SST20 emitter, available in either 6500K or 4000K. I chose the 4000K variant and I highly recommend you do as well. They don’t advertise the 4000K as 95CRI, but I’ve never heard of a low CRI SST20 4000K and it looks the same as my other SST20 4000K’s so I’m convinced it’s high CRI. It sits in a surprisingly deep, smooth reflector with excellent centering. It appears to be held in place from the driver side so I did not attempt to disassemble the head. I love this emitter choice because it looks great and it’s very small so you still get some decent throw despite the tiny reflector.

Update: This Reddit user tested and verified that the 4000K variant is high CRI.

It’s worth noting that it does not zoom or focus, despite what the Amazon listing says. I’m glad it doesn’t.

The beam is just lovely. It’s a delightful 4000K with satisfactory tint and no tint-shift. The hotspot is just the right size where you get some throw but it’s also useful up close. There are no artifacts and the spill is usable. I do think it would have been cool for Wurkkos to use the TIR from Sofirn’s C01S here as it provides more of an inspection-style beam that I find fun in penlights. There’s really nothing to complain about with the beam and it’s a joy to use.

Inside is where WK02 really shines. It’s the perfect size to carry around at home or at the office where you aren’t likely to need a lot of lumens. I find that low mode is sufficient for most indoor tasks, and I occasionally bump up to medium. High mode is bright enough to be pretty impressive and it will light up a room.

Outside it doesn’t win any awards for brightness or throw, but I find that medium mode is plenty for navigating around, and you get plenty of runtime too (over 4 hours with Eneloops). High mode will give you a little extra punch when you need it but it’s not really a substitute for dedicated high powered light for outdoor exploration.

Moonlight Comparison from left to right:
Sofirn C01S
Xtar T2
Wurkkos WK02
Thrunite Ti4 NW
Sofirn SC21 5000K

Moonlight isn’t offensively bright, but it would be nice if it were a little dimmer.

Tint Comparison from left to right:
Sofirn C01S (unknown bin)
Fireflies E07x Pro (FA4 bin)
Wurkkos WK02 (unknown bin)
Emisar D4V2 (FA3 bin I think)
Convoy M1 (FB4 bin)

It’s hard to pick up the differences in tint between these various SST20 samples, even with my own eyes. They have a reputation for being slightly green at low levels but I don’t see any significant amount of green in my WK02 sample in any mode. It’s not quite as rosy as the FA4’s in my E07x Pro, but it’s not bad by any means. It’s certainly much nicer looking than the 6500K version. I have found the tint to be perfectly satisfactory.

Driver

There’s not much going on in the driver. I suspect it wouldn’t be too hard to remove if are were so inclined. There are a couple of holes that you should be able to get sufficiently needle nosed pliers into to unscrew the pill. The positive symbol sort of looks like a Philips head screw, but it’s not deep enough for that. I think it’s actually meant to be a plus sign indicating the correct battery orientation.

Design & Construction

WK02’s design is simple and I like it. It manages to look neither cheap nor particularly elegant.

Overall build quality is solid, especially considering the price. The threads on the head are trapezoidally cut and very smooth. The anodizing is thick, evenly applied, and a pleasant texture. The knurling adds a bit of grip near the tail but isn’t too aggressive.

The tailcap is removable, but it’s had blue loctite applied so I had to use some extra grippy gloves to get it off the first time. The threads are un-anodized, un-lubed, and triangle cut, but you probably won’t ever need to remove it so it doesn’t really matter.

Switch

The switch is a forward clicky mechanical. It sits behind a proud, grippy, rubber boot on the tail of the light and I love it. I have a strong preference for forward clickies over reverse clickies because I can get to whatever mode I want before fully clicking on the light. It also allows for momentary use. This switch is tactile and easy to activate. During my time carrying it, it never turned on in my pocket by accident. Plus, thanks to the fact that it always starts on low, the likelihood of it getting turned on in your pocket and being on a high enough mode to drain the batteries is extremely low.

During the first two days of testing, I did notice that the switch would occasionally stop working. The light would simply flicker as I actuated the switch. It happens so infrequently that I thought it was user error at first. This issue disappeared after the second day, and I’ve been using it for a few weeks now with no issues whatsoever. I suspect it was just a case of the switch breaking in or something.

The switch boot is simply too small and flexible for tail standing to be possible. Mine is also ever slightly crooked.

Carry & Ergonomics

Ergonomically it’s similar to most other penlights. It’s quite narrow and a little bit slippery on the body. The switch is accessible and easy to activate though. It works best in a reverse grip, but a cigar grip or even a pen grip work fine too.

A basic pocket clip is included with the light and it works well. I think it would have been nice for Wurkkos to use a collar style clip that carried deeper, but since the light is so long and narrow this clip works just fine.

I carried it in my pants pocket briefly, but where WK02 really shone was in a shirt pocket. I found myself carrying it there in conjunction with a larger, brighter 21700 light in my pants pocket. I used WK02 when I needed hands-free light since I am able to hold it in my mouth comfortably for a few minutes at a time. That’s not something I can do with my main EDC light, a big, heavy, Fireflies E07x Pro. The distance between the bezel and the pocket clip was perfect for fitting it in my particular shirt pockets. Perhaps that’s why a deeper carry clip isn’t included.

Batteries & Charging

WK02 is designed to run on two AAA batteries. They can be Alkaline, NiCD, or NiMH chemistry, but I highly recommend NiMH since they are rechargeable and high capacity. I used white Panasonic Eneloops and a one pair of generic alkaline cells for all my testing. The batteries go in with the positive toward the head and none are included in the box.

Competition

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

Lumintop IYP365: different (but still good) Nichia 219 emitter (there’s also XP-G3 but don’t get that one), collar style clip, metal reverse clicky switch, usually slightly more expensive, a little bit nicer looking design, lowest mode is 3lm so no moonlight, mode memory. WK02 wins in my book for having a moonlight mode, forward clicky switch and always starting on the lowest mode.

Nitecore MT06MD: designed for medical professionals, collar style clip, metal reverse clicky switch, no moonlight mode, highly sought after Nichia 219B emitter (5000K), constant current driver, always starts on low, usually slightly more expensive. WK02 wins in my book for having a moonlight mode and a forward clicky switch.

Streamlight Stylus Pro: single mode (100lm), forward clicky switch, usually a bit more expensive, cool white low CRI higher efficiency emitter, slightly deeper clip, numerous body color options. WK02 wins in my book for having more modes and a nicer emitter.

Foursevens Preon P2 MKIII: significantly more expensive, ultra-classy design, collar style clip, forward clicky switch, different (but still good) Nichia 219C emitter, multiple material options, highly configurable UI (including multiple types of mode memory), proper moonlight mode, does not support alkaline cells. This is without question a better light, but it also costs 3-5x as much.

Conclusion

I haven’t ever had a great deal of interest in penlights because they seem to trade a lot of performance just to make the light a little thinner. But man, I get it now. WK02 is so narrow and so light. I accidentally carried it and my Fireflies E07x pro for half a day without realizing WK02 was on me! It’s just fun.

Wurkkos knocked this one out of the park. The only things I can find remotely wrong with this light are minor nitpicks. The UI is excellent. The switch is excellent. The beam is excellent. The build quality is excellent. The price is excellent. If you’re in need of a penlight running on AAA’s, just buy this one already.

Thanks to Wurkkos for sending me this light for review!