CooYoo Particle L (totally not MecArmy PT16) review

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CooYoo Particle L (totally not MecArmy PT16) review

I bought this light from a group buy here on the forum. It was originally listed as “Brand X” but I knew what was up because I’d been keeping an eye on the MecArmy PT16 since it came out, but when it actually became available the brand was CooYoo, Particle L. While I am honor bound by the “don’t share group buy prices” code of the knights of the BLF I will say that it was a few dollars cheaper than the best sale price I’ve found for a PT16 and in line with other group buy codes I’ve received on this forum. This wasn’t in exchange for a review or any other compensation.

The Particle L in no way should be mistaken for a MecArmy PT16 for you see they couldn’t be more different. Observe:

(PT16 for reference from will34’s review) Clearly the Particle L is blurrier and has sadder white balance.

There that should settle it. Just in case though I’ll make numerous references to the PT16 throughout my review.

TL;DR Up top
Bright super compact triple is an awesome idea. Some odd design choices could be overlooked, like an easily activated switch or lanyard-only carry options but the bottom line is that a well built light is ruined with a terrible UI. Appears to be discontinued (for good reasons) v1 of the PT16 UI. Constant design changes make this light not worth the risk.

Obligatory box shot

Hey wait a second, that’s more of a blister pack than a box. In case they want to sell these at AutoZone or something. Please note that it has stuff, including paper stuff, that you can not read at your leisure, and o-rings galore.

The back has some quality engrish including this gem: “Please do not direct human and animal eyes!” Film majors listen up: this is not the light for you, even for your puppy movie.


Flashlight roll call

From left: CooYoo Particle L, Zebralight SC32, Olight S20R, Sunwayman V11R, BLF A6 (3D tint, unanodized shorty tube), Nitecore MH20 CW

Flashlight nap time

I like pocketable lights so I feel like I have a pretty good cross section of what’s available out there for maximum compactness, but I don’t have any other triples or any other TIR optics. The Particle L would be the shortest if it didn’t have it’s weird trident prongs on the back. An Olight S1 (non rechargeable, TIR version of the S10RII pictured) would be even shorter. I put the MH20 in there, even though it’s 18650, to have something that could compare width wise to the triple emitter of the Particle L. The Particle is definitely pocketable, but as I’ll cover later it’s also very _hot_pocketable.


Finish is really nice. Completely defect free. I like the “pineapple” knurling or whatever they are calling it. I give the bezel 6 out of 10 for it’s accidental table scratching ability (where a 0 is OK to put on your antique desk that they signed the constitution on and 10 is a total table ruiner). I’d prefer a little less sharp because let’s face it: you aren’t going to be striking any attackers with your 2.5” flashlight.

It comes apart:

Both sets of threads are nice and square, spin very smoothly, and arrived bone dry (easily fixed). One o-ring in the front and we-mean-business-double o-rings in the back. It’s not just bad staging, the battery has no brand name whatsoever.

The little button that connects the battery tube / case to the emitter head is springy to ensure good connection.

The trident things in the back ensure a good tail stand, but also add length. Also, also, they leave room for a magnet:

This is just holding on to the battery, later I’m going to epoxy it in.

Overall the build quality is very nice.

I can almost guarantee you are going to accidentally activate that switch while this light is tumbling around, clipless, in your pocket. Don’t be caught on the street using that lanyard. Lanyards are the fanny pack of the flashlight world.

I saw in this PT16 review on reddit that his PT16 came with a battery sleeve and the tube was wide enough for an 18350. That is not the case with mine:

With the 16340 battery in place you can see it’s pretty snug. There is no battery rattle at all in my Particle:

It charges with a micro-usb cable, as advertised, which is pretty cool. This is the smallest light I’ve seen that on. Taking the head off to charge it is annoying, might as well take the battery out, but at least this way all you need is the cable you likely already have to charge your phone and this design lends itself to better water proofing.

Bezel came right off, no loc-tite, to access the shallow triple optic and aluminum star:

There appeared to be a teensy amount of thermal paste behind the board, but you have to really get back there to look for it. Solder joins are passable. I tried taking that screw off, but it didn’t help anything come out. I suspect there is some trick to taking the button off and then maybe the pill can be squeezed out?


Oh dear, CooYoo, MecArmy, or whoever you are. What were you thinking? This appears to be the discontinued v1 of the PT16 UI. Your options from off: press for less than a second for momentary turbo, press for greater than one second to stay in turbo. Then you can “short” press (up to one second) to advance modes or longer to turn off. Double click from off or on goes to strobe.

I think that description speaks for itself. If it isn’t plainly awful to you then I’d like to say “Welcome to BLF, how many minutes have you been a member?”

I’ll point out a couple nice things in fairness before I elaborate how this is an awful UI. Momentary on to turbo is cool. Just gives you a quick burst of light, almost like how you can use a forward clicky switch on a tactical light. The low mode, while not a moonlight, is somewhere between moonlight and low of my S10RII. I expected from other reviews a too-high-low due to the triple emitter. I can’t measure it until my BLF Integration Sphere gets here, but I’m happy with the low. Also the strobe mode is pretty cool (the sound of a hundred BACK buttons being pressed). Let me explain since I don’t want to submit you to a shaky cell phone video of a flashing light. It has a somewhat unique strobe: it blinks medium speed (about 5 Hz) for 2 seconds followed by fast strobe (about 10 Hz) for one second. Strobes are pretty pointless, but I like this one. It’s distinctive and attention getting. SOS, which even strobe apologists can agree is truly pointless, is further hidden behind another long press where it can safely be ignored.

Let me be clear. The UI is garbage. Want a low level because it’s late and you don’t want blinding 1000 lumens? Here you go, but first, how about just a second of those blinding 1000 lumens. Enjoy the spots when you blink your eyes. Want it to stay on turbo for more than a second? Not if last had it on a different mode. This light really lacks for shortcuts-from-off to high or low.

I’ll reference the earlier picture where you can see inside the head that there are landing pads for programming pins. I hope someone figures out how to flash some decent firmware on this thing. Why don’t the manufacturers open source their firmware? They already copy designs left and right. Just let us enthusiasts get the UI we need.

Beam Shotz
My second take on Beam Shotz. I fiddled with the white balance to get the closest of the WB presets to how the tints actually look. It’s not perfect, but it’s better than my last review of the Thorfire C8s. I don’t have any cool things to take pictures of. I can’t even go white wall hunting. This is white ceiling hunting. About 7 feet above the front of the lights. All shots are manual exposure 18mm focal length, f/3.5, 1/125 exposure and ISO800. The order is the same as the line up shot from earlier in the review.

Particle L

Key features: All flood, all the time, I don’t have a camera lens wide enough to show all the flood. It floods. More of a hot area than a hot spot that smoothly floods itself out to nothing. Tint is decent. It’s a cool white, but not annoyingly “one-bin-too-low” blue LED cool, just slightly cool.


Key features: Not as floody, not as bright. Difference is more pronounced over greater distance


Key features: ok the tint is kind of green. We’re not reviewing this light. The beam has a lot less flood than the Particle


Key features: I love this beam. It has a great balance of hot to spill with a smooth transition and doesn’t spread out too fast. Particle has almost identical tint

BLF A6 (3D tint)

Key features: I swear this is the 3D tint and not the 5A. At least that’s what it says on the box. My white balance setting is making it yellower than it is. Anyways key feature is that this is my only light rated greater than 1000 lumens. Even though it’s not as floody it is throwing more light out there and it shows up on camera better


Key features: Another light close to 1000 lumens, but more throwy. Much more concentrated beam.


It’s well built, clearly the same factory or whatever as the MecArmy PT16, but without the improvements made to that light since launch. At this point I wouldn’t even recommend getting a PT16. Even reviewers of that light are getting different models each time. Sometimes there’s a bad UI, sometimes there’s a battery tube adapter. You just never know what you are going to get. I’d take that chance with a $20 flashlight but before the group buy price this one is about $60. At that price you can get a Zebralight with much more consistent quality.

Edited by: sb56637 on 09/02/2017 - 12:11
The Miller
The Miller's picture
Last seen: 2 months 3 weeks ago
Joined: 12/14/2015 - 12:08
Posts: 9908
Location: Charente France

It is a nice read for sure.
But I cannot see your pics. Especially the first with yours having less good white balance I really want to see Wink oops there they are.

pacbough's picture
Last seen: 5 months 2 weeks ago
Joined: 08/29/2011 - 08:10
Posts: 349
Location: Adelaide, South Australia

Thank you for the review. I was waiting to see what the UI was like before I bought one. Glad I waited.

will34's picture
Last seen: 2 weeks 13 hours ago
Joined: 12/18/2012 - 00:12
Posts: 3694

Thanks for the review! The V1 UI… what a way to ruin an otherwise very fine keychain light. V2 UI is much better by the way.

Been using mine for months now and I don’t plan to replace it with anything else. That until I find a way to open my Fenix E15 and swap an XP-L HI with a FET driver.

I also considered modding my PT16 into a quad but the stock optics throws great, they may look like a Carclo but this is a superior optic.

Last seen: 6 days 21 hours ago
Joined: 02/05/2016 - 23:44
Posts: 154
Location: Texas

Yeah. The pads on the driver are for programming the chip. A long time ago I’ve built jigs with pogo pins for reprogramming chips in circuit such as this. I’d be willing to do that again if only I had access to the source to build better firmware.

WolfA's picture
Last seen: 10 months 3 days ago
Joined: 02/11/2016 - 08:47
Posts: 258
Location: Vienna, Austria, Europe

Great review and very funny to read!
Sadly it’s absolutely true what you write about the UI. I got mine yesterday and have to fully agree:


"A black bulb which, when switched on, turns the room dark"
(Gyro Gearloose)

Pulsar's picture
Last seen: 3 months 3 days ago
Joined: 07/29/2011 - 00:41
Posts: 5840
Location: Maine

Anyone know if these have the newer firmware​ now, like the me army?