Convoy M21B, M21E, M21F w/ GT-FC40 4500k: 3 CRI-95 324m throwers w/ Nichia-like tint -->3 home runs. Rec w/out reservation :-).

(EDIT 4/17/2022 A few weeks after I had bought M21B, Convoy released the new *M21E and M21F, both using GT-FC40 but with three crucial differences from M21B. One, E and F have side switch, two, they have on board USB-C charging, and three, the User Interface is different from the 12 groups UI of M21B. I now have all 3 and will add review of the new lights to this thread, originally about the M21B.)

Convoy M21B and S21D are Convoy’s fairly recent releases of lights with top-notch CRI and 21700 batteries. Whereas S21D has limited throw (more useful around the house) and employs Nichia LED’s famous for their unmatched color rendering, the M21B uses Getian GT-FC40 4500k and is clearly designed with better throw and “functional brightness” in mind. It is an all-around EDC that possesses the extremely rare combination of throw and world class CRI. It’s useful for many tasks: around the house, evening walks, and as a great gift light (or should I say great CHEAP gift light O:) ). You could tell your friend s/he holds one of the very best flashlights available on the market today, regardless of cost.

The GT-FC40 LED used in the M21B needs no introduction. Like Nichia, it is very well known for its beam color and has been used in some very well regarded lights such as Acebeam EC70 and Convoy’s own S12. In the M21B with its large and deep orange-peel reflector, the throw was measured to be 280 meters on 100% mode by “this excellent review by ”Axios”“: Although I could classify 280 meters as medium throw (not ”super”), AFAIK this is the longest throw for this Getian LED in an EDC. A combination of throw and great LED at the give away 30 buck cost makes this light an extremely compelling purchase.

Size wise, the light is typical EDC; it is slightly large at the top end but still very much pocket-able. The top end is not nearly as cumbersome as the Sofirn IF22a. Knurling is OK, not as deep as Emisar for example but at this price I am not complaining. The crenulated bezel is gentle and not as painful to touch as the sharp one on Olight Pro Warrior (sincerely hope I will never have to use it). I like the flaring large top end, hinting at its aggressive “throw” function, like the wheel arch flare of sports cars declaring cornering speed. I prefer color finish and would gladly pay more if it’s available, but right now the only finish available is black.

The light is hot during test run-down from Turbo, but in actual use outside, there is no problem at all. I understand the thermal limit is set at 55 degrees C. The UI is not Anduril so there is no messing with setting temperature. There is no on-board USB-C charging, hopefully the next step for Convoy lights. Lanyard is supplied but no clip. If anyone knows a clip that fits M21B please post.

Interesting or important post in this thread:

* Comparing the 3 lights M21B, M21E, and M21F: Click Here

* External Temperature Measurements & Thermal Mass Consideration (Important) M21B, M21E, and M21F: HERE

* 4 Lights I would buy were I to start from beginning HERE

* Convoy Accessories HERE

* Effects of Convoy “Green Tint” AR Lens on Duv +*HERE and white-wall beamshot HERE

* Specs from Simon: Here

Convoy Accessories Review - IMHO YMMV

Clip-on Clip A little too small at 22 mm diameter so I could see a little air gap between clip and light. I would have preferred probably 25 mm. Fits S21D, M21E (after bending clipping arms outward a little). Might fit M21B and M21F but I didn’t try because it’s tight and I didn’t want to scratch the finish. I much prefer the screw on clip (better in every way IMHO), but if this is what you like, I would bend the arms outward a little so that it doesn’t scratch the light’s finish.
Screw-on Clip Perfect for my need. Fits S21D, M21B perfectly, does fit M21F and likely E, but would help if the screws are a little longer for absolute secure attachment. Ok I hope what follows makes sense: For the Convoys with the side switch, M21E and M21F, I prefer to keep the clip at 9 o’clock position (90 degrees to the left of the switch) so that it doesn’t go under my right hand grip. For the M21E the holes are perfectly placed so I use screw-on. For the M21F the holes are not, so I use the clip-on, after I’ve bent the clipping arms outward.
Metal lighted switch IMHO mandatory :slight_smile: for S21D and M21B. For switch color I chose blue because of less current drain vs orange (9.4 mA vs 14 mA). The metal switch has a wonderful nicely tactile click, more defined in its action and night and day better than the rubber version. For me, it is especially critical for the 12-GROUPS UI used in these lights because in this UI both click (full click) and tap (half press) are important, and the tap is so much easier with it. The metal switch has a built in half-way stop for the tap’s half press and it makes all the difference IMHO. Install takes 5 minutes, completely plug and play. The most challenging step is to remove the retaining ring which is very tight and would likely be difficult if you don’t have something similar to this needle point pliers .

Driver & UI: Boost, 12 groups for M21B, side switch UI for M21F and M21E
Temperature protection management inside (Factory set at 55° C.)
Low voltage warning: Yes (The light flashes when battery is low.)
Lens type: AR-coated glass with green reflection (the good type that drops Duv about 20 points)
Reflector: orange peel
Mode memory: Yes

Measurements from Simon:
GT-FC40 4500k
CCT 4521k
Ra 93.2
R9 76
R12 70
Duv +0.00215

GT-FC40 5500k
CCT 5598
Ra 93.6
R9 78
R12 73
Duv –0.00007

Good Measurements from Zero Air Report FC40 4500k in Convoy L6 HERE
Level 4 Ra=93 R9=76 Duv 0.0016
Level 1 Ra=95 R9=98 Duv 0.0001

Measurements by me and my Opple Lightmaster Pro :+1: :slight_smile:
No change in Duv noted with time (heat).
Lower intensity drops Duv 30 point: Convoy M21B 1% –0.0082, 35% –0.0050

M21B 4500k
CCT 4579 Ra 98.7
x 0.3560 y 0.3466 –0.0068 (2nd measurement –0.0046)
Throw 262 m
Flux 2250 lm

M21F 4500k
CCT 4481 Ra 98.4
x 0.3591 y 0.3491 Duv –0.0066
Throw 273 m
Flux 2150 lm

M21F 4500k (second light - strange outlier w/ visibly very magenta center - don’t think it’s normal)
CCT 4370 Ra 97.9
x 0.3595 y 0.3339 Duv –0.0148
Throw 276 m
Flux 2220 lm

M21E 4500k
CCT 4395 Ra 98.2
x 0.3623 y 0.3520 Duv –0.0063
Throw 324 m
Flux 2140 lm

M21E w/ Getian GT-FC40 5500k
CCT ~5300 Ra 98
Duv first turn on (cold): low brightness –0.0004, high brightness 0.0004 (second measurement 0.0004)
Duv after 30 min (hot): low brightness –0.0018, high brightness –0.0007
Throw 332 m
Flux 2220 lm

About the attention grabbing title, Nichia-class tint :innocent: . I knew the GT-FC40 was something special immediately with first turn-on during my walk. Scenes look almost like my Emisar 219b 4500k, something no other LED could do, including Nichia’s own 519a, which looks more golden/yellowish than 219b.

The pictures confirmed my suspicion. During processing I would sometimes have some difficulty distinguishing GT-FC40 from the legendary Nichia 219b. Even this morning I had to double check the shots again so I don’t make a fool out of myself LOL.

In the picture below on the left side one of the question mark is GT-FC40 and the other is Nichia 219b sw45k. There are certain clues that help me now but initially there was a confusing & uncanny resemblance, as if Getian engineers had taken or duplicated Nichia’s phosphor :smiling_imp: :slight_smile: .

(Edited re-post.)

I’ve compared GT-FC40 against some excellent and well known LED’s in the 20 or so lights I have: Nichia 519a, Cree XHP35 HI, Samsung LH351D, Luminus SST20 (all of them I like). Here is the most “challenging” comparison for GT-FC40, against the hallowed Nichia 219b 4500k .

Nichia 219b is a legendary LED. Its Ra value is a gazillion, its R9 a half gazillion lol. People fall in love with the magenta tint. It’s still the king for accurate rendition and making colors pop. As seen in the pictures below, the GT-FC40 comes closer than any other LED’s in matching the 219b’s fantastic color quality. This is why I’ve called it the Nichia imitator. Its magenta tint is unmistakable.

Does GT-FC40 in M21B have any advantage over 219b in my Convoy S21D? Yes, when it comes to throw and brightness in these small lights, GT-FC40 wins over Nichia by a wide margin (it’s not even close). At present time, if you are looking for a throwy light with legendary magenta tint and color accuracy, this LED is your only choice IMHO. Although the throw of Convoy GT-FC40 at ~280 meters is to me still medium class (ie not super like 600-700m), at this point this LED is the very best choice for a throwy EDC light with top class CRI and tint. At $30 bucks a pop, the Convoy is a tremendous value and no-brainer must-buy :slight_smile: . All IMHO

I am definitely picking one of these up!
Any idea whether or not this <a href=>lighted switch can be used with this variation?
Im not sure if theres anything special about the driver used with this LED that would make it incompatable with the lighted switch for some reason.

Both of those features require, really, an e-switch. The M21B, with its power switch is never going to get either.

The M21D and M21F have usb-c charging, but not Andùril. And they will be available with the GT FC40 soon.

I love my FC40 M21B. It’s a great host with a great emitter.

ETA: Dunno why I left if off, but the M21E is also an e-switch host that will eventually get the FC40.

Your link is broken.

Anyway, I have put on the Metal Lighted Switch on M21B GT-40 and works fine.

Metal Lighted Swtich

I have also ordered Rubber Lighted Switch where the switch are identical. It should work too.

Rubber Lighted Switch

I think ive fixed the link.
Awesome, thanks!
Just ordered both.

(Repost of summary from later discussion in case you missed it.)

A summary from my experience with the 3 lights.

Beam: Has brightest and most useful spill of the 3 lights, but less throwy. Probably as a result of the smaller thermal mass and less effective cooling, from a Turbo start I’ve found this light steps down sooner than M21F and E. Throw measured to be 280 m by Axios. Hotspot initially slightly dimmer than M21F, but once thermal regulation step-downs have set in, brightness is very similar to M21F. Overall this light is close to the M21F.
Construction & cosmetic:
No onboard USB-C charging. If you want a Convoy GT-FC with rear switch, at this point this and the smaller S11 (thanks @undefined for the correction) are the two choices.
It’s a very good looking light. Smallest of the 3 lights and pocketable. Knurling is not as deep as Emisar for example, but at $30, I am NOT complaining about anything.
I would highly recommend to change rear switch to metal switch from Convoy as it makes the light very pretty and more importantly, makes the click (full press) and tap (half press) much easier, for me anyway.
UI: The well known Convoy 12 Groups. I prefer Anduril but whether 12 Groups is a plus or minus is of course personal preference.
No Anduril means you cannot play with settings such as thermal regulation’s max T (factory setting is 55 C per Simon). Judging by the result (similar step-downs to other lights I have), maybe there is no need.

Beam: As these GT-FC Convoys get larger, spill becomes dimmer and hotspot becomes brighter. The M21F has a slightly brighter hotspot than M21B. Overall this is a similar light to M21B.
Construction & cosmetic:
Among first Convoy lights with onboard USB-C charging. A very good looking light. Top end is not anodized and not smooth to turn the first few times but now is better.
The side-switch: it “clicks” very nicely, but is hard to press, so not my favorite. My firsts 21F’s switch has a dead zone and needs to be clicked at dead center, which is not always possible. Simon immediately sent a second light without charge and its switch is good.
The side switch is also in same position as the charging port, so I would definitely recommend screw-on or clip-on Convoy clip for example at minus 90 degrees from the switch to locate it quickly.
UI: Still no Anduril, just Convoy UI for Side-Switch lights. Personally I like this UI and prefer it to the 12 Groups.

Beam: Brightest hotspot, best throw, and dimmest spill of the 3 light, but the spill is still bright and functional. Meaning the beam is balanced and like the other 2 Convoy’s makes for great all around multi-function, multi-use EDC light. Larger light has more thermal mass and better cooling, and this means for example step-downs in this light occur a couple minutes later than M21B and F.
Construction & cosmetic: I am not too thrilled with those diagonal grooves at the head of the light but otherwise it looks good. This size fits more easily in jacket pocket, unless you have loose pants with side pocket (not jeans’ front pocket). I do carry it in side pocket of my pants.
The side switch is same as M21F: Beautiful but short travel and hard to press. This means single click is easy, but multiple clicks are not. OTOH the good thing about this is it protects against accidental activation of the light, which is not a good thing in this high-power light.
UI: Same as M21F, UI for Convoy Side-Switch lights.

IMHO the combination of smallish size and USB-C charging makes the M21F sort of the sweet spot of the 3. OTOH because it is so rare to find a bright throwy light with world class CRI and no green tint, I like the M21E best. Its disadvantage is that it is also biggest and heaviest, and that large top is unwieldy. Lastly, if you like floody light and tail switch, and don’t mind the lack of on-board USB-C charging, then M21B is the one. One of these GT-FC40 4500k plus a Convoy S21D with 219b 4500k would make an incredibly inexpensive and fantastic start/back bone for any light collection with accurate color rendition in mind. You can’t buy anything better even if you want to spend more money IMHO.

Thanks. Does the metal switch fit in other Convoys such as S21D? Is it easy to install, no soldering needed?

Is there anything you don’t like the metal switch that made you also order rubber switch?

Yes, I have put on a Metal Lighted Switch on my S21D and works fine.

It’s almost a plug and play thing. But you need a least a tweezer or a long nose plier for the job…

I like both Metal and Rubber lighted switch… To your question, aesthetic aside, Rubber Switch can Tail Stand but not the Metal Switch…

Btw, the M21B could be ordered with Littokala 5000 mAh battery. I’ve compared this with Samsung 40T, an un-protected cell with high current capacity, and noticed no difference in brightness. The Littokala of course has more capacity than 40T (4000 mAh) and measured well with my Opus.
M21E and M21F of course doesn’t need battery charger since they have on board USB-C charging.

Samsung 40T 21700 Flat Top Battery for Convoy: Samsung 40T 21700 4000mAh 35A Battery - INR21700-40T

Opus BT C3100 v2.2 charger from legit AliExpress store: Opus BT C3100 from AliExpress is about half the cost of same thing on Amazon. The seller I quoted is legit and the thing came in around 10-12 days IIRC. AFAIK Opus is one of the few chargers that could test internal resistance and capacity accurately and highly recommended.

XTAR MC2 charger much less expensive XTAR MC2 2 Bay USB Battery Charger - Portable Micro USB Charging

Opus BT C3100


As mentioned above Convoy has released other hosts for this LED, most notably now with on board USB-C and very likely different beam patterns. I have two of the new hosts, M21E and M21F, on order and probably will merge it with this thread to compare beam shots (throw, spill, beam angle, etc.). You might want to consider these two, or wait a couple weeks to see what I find. GT-FC “eats” battery especially used at 100% brightness so on-board USB-C is a welcoming change.

LED wise, I’m reconfirming that this GT-FC LED is the greatest Nichia imitator :) that I have in my collection. It is NOT exactly Nichia (GT-FC has more positive Duv, less magenta, more magenta-brown), but color rendering in real life use is very similar. Ra and R9 numbers are top notch. All this making M21B and likely the other 2 M21’s an all-around multi-use EDC with THE best tint on market now IMHO. “Arrived at departure transport hub” I can’t wait to get my hands on the E and F versions LOL.

In my living room, against the wall of truth :innocent: . While GT-FC40 is NOT 219b (IMHO more brownish magenta for FC40, versus true magenta of 219b), the overall picture partly explains why I had some difficulty telling them apart with the garden shots in my front courtyard.

In fact when it comes to imitating 219b, one could almost say GT-FC40 out-Nichia another Nichia lol, the 519a with its warm yellow tint.

Pleas ignore the note about hotspot vs spill color rendering for the moment (something noted in throwy lights with bright hotspot, where you see 2 color zones as a result). That’s topic for another discussion :slight_smile: .

IMO, the 519A and GT-FC40 look the best overall, as the 219B looks too rosy, and the SST-20 is more throwy than the others.

Below are close-up crops of the above picture. My son’s USC red cap against the very slight off white window blind. GT-FC40 renders the off white color IMHO best, very close to 219b 4500k which tints the blind a little grey-magenta’ish. Red cap is also rendered very well - extremely close to the color in real life. R9 (strong red) is very hard to achieve, anything above 50 is considered good, and GT-FC40 with R9=76 is approaching top class rating R9080.

Pictures are starting to emerge pun intended that this GT-FC40 is for real when it comes to color rendering. :slight_smile: The shots duplicate what I observe in real life.

These living room pictures are from a few days ago. Yesterday I took pictures of neon pink and yellow flowers, plants, and trees in the front yard, in the dark of night (this hobby - I’m sure neighbors are like WT* lol). Very interesting result again showing the fantastic ability of Nichia 219b to render flora and fauna, with GT-FC40 awefully close to matching it. Will post that next.

For a frame of reference, I will first compare Nichia 219b and 519a.

It’s interesting to note that without a lightly colored background such as my living room’s light beige wall (versus dark green background of this picture), the magenta tint of 219b is not as easily noticeable. In addition, differences between LED are more subtle. The easiest way for me to tell which LED is which is the flat grey surface of the palm tree. Here the more yellow tint of 519a is more obvious.

Looking at the hot pink geranium flowers, 219b somehow just seems to make the flowers stand out more from the leaves. More depth and 3D, color differences more distinctive - just my subjective opinion so if you don’t see it, I won’t argue :-). It will be interesting to do a crop comparison.

I am fairly hard core into photography, and this shoot-out has been very interesting because it confirms this observation I have about 219b in real life viewing: colors seem to “pop” against background, for example blue rosemary flowers against the green leaves.

To my eyes the hot pink geranium is rendered extremely well with 219b. Flowers pop against the green leaves, achieving depth and a 3D effect not seen with 519a, IMHO. The effect is so strong I had to go back and check if my 519a shot is out of focus (it’s not).

Second, the hot pink color itself is rendered with much more accuracy with 219a than 519a, where there is a yellow tint to the flower. This is not a surprise as 219b has about the highest Ra and R9 of any LED’s. The next question is of course, how would GT-FC40 fare against the gold standard 219b?

I still can’t get over the pink bark.

Also I think the main reason why the pink flowers pop more on the 219B image is because there’s harsher shadows behind them. If you white balance both pictures to the tree bark in lightroom, the differences are in flowers between the two are negligible.