Review: Convoy M21A SST40

6 posts / 0 new
Last post
Lumeniac's picture
Last seen: 26 min 51 sec ago
Joined: 12/19/2016 - 13:47
Posts: 604
Location: Russia
Review: Convoy M21A SST40

Convoy goes along with trends in industry and released some SST stuff this year. This time i`ll tell you about Convoy M21A, and next review will be comparision of L21A SST40 and L21A XHP35

you can buy Convoy M21A at Aliexpress | Banggood| Gearbest

21700 battery

There are no specifications and beautiful promo pictures, it’s a Convoy.  


This flashlight came to me in the cheapest and usual white box , usual for all the Convoys. I am ready to admit that later it will be possible to see the packaging better, the thick beige box, in which M3 \ L21A now go. Overall, everything is as usual. Yes, the phrase “everything is as usual” can completely, completely describe everything regarding appearance.

By and large, outwardly this model looks like the same C8, which, with the same head size, has little bit larger body, which now has to store larger battery. That’s all. Not the slightest “high design” and other tricks of appearance here. Just a flashlight in all its functional simplicity. Another Convoy, in other words. Want something prettier? Prepare to open up your wallet, man..

Convoy M21A is controlled by a tail button. .

The springs look the same as in C8. The difference is that they are shunted, it’s understandable – amperage with the SST40 will be muc highter. As we say in Russia, “it will eat ampers in three throats”. Not that there was any functional difference, but I would prefer a solid double spring.

The thread is rectangular, medium in size, well lubricated. As I already wrote, it is extremely preferable not to take risks and take 21700 battery from Simon. Litokaala`s one will simply not fit.

The knurling is completely simple, the same as that of the same C8s

The dimensions of the flashlight are larger comparing to C8, head is the same (completely comparable to C8), body is larger. The cooling fins are quite deep and wide relative to the dimensions of the head.

I did not feel any inconvenience in weight distribution. The grip is quite comfortable.


Glass with AR coating

Traditionally, the head can be disassembled easily , this is the Convoy, in which there was always the easiest access to insides.

The reflector is smooth.

Copper plate with SST40 pulled bolts, which makes practical sense. I read that in the maximum mode the heating is such that the wires can solder out – you need the maximum contact of the MCPB with the head. Otherwise, go ahead with the purchase of a new MCPB with LED

That’s all. What outwardly, what in terms of workmanship is a completely ordinary Convoy flashlight – with all it`pros and cons.


p=. UI

There is nothing new either, UI is the same as it was in bunch of Convoy models. Click for off-on and switch modes. Maybe there will be some alternative firmware, but now everything is as simple as possible. Since in this case, a good stabilization also comes aling wth this simplicity, I will definitely prefer it to the wealth of choice of different presets like in C8 +.


p=. How the Convoy M21A shines

Two options are now available, 5000K and 6500K, I got the first one. I did not have the opportunity to compare them live, but I’m sure that there will not be that difference in brightness that would justify the purchase of a version with cold light.

The flashlight gives a really bright light (declared 2300lum). Such brightness from an average-sized LED results in a combination of good range and a fairly comfortable side fill. It is also true that at the same brightness as the Convoy C8 + XPL-Hi, this flashlight will be less long-range.

In this model, thermostepdown is declared – and this is a completely reasonable solution, without it, at maximum brightness, the flashlight would warm up to such a temperature that the body itself would start to emit light.

Attention! The specification states 30%. My measurements with a luxmeter clearly show 40% -100%. And after the thermal stepdow, brightness falls to this level.
so this number will be given below.


The graph shows a very good picture. 2 hours of stabilized brightness by 40% (and this, sorry, about 1000 lume and further you will see that this is definitely working brightness)
Also on the graph are shown the indication of battery discharge by flashing once every 5 seconds, somewhere from 3.2v. At 2.9v, the flashlight turns off.

Cooling allows you to achieve about half an hour of work at close to maximum brightness, then it falls. To the same 40%, the brightness drops about half an hour, bringing the overall good brightness to the total hour.

By the way, heating is 100% balanced on the verge of comfort. If you do not squeeze the carcass tightly in the region of the head, then the norms. If there are no plans to constantly shine at 100%, then all the rules.

I have no complaints.

and if I compare with C8 +, then look at the graph for this model, everything is clearly worse, agree.

Currents: 0.01-0.183-1.84-3.4A (but you shouldn’t rely on last one,i cannot measure currents above 3A, as a rule). All the same, currents are more needed to evaluate the duration of the work, but it is on the graph. And here, by the way, the ratio of 2-3 modes for current consumption is quite consistent with the stated 3-30%. weird …


Well, the light itself, see for yourself.

If you describe in words how the Convoy M21A shines live, then by the ratio of the sidelight and the center, visually the flashlight reminds me of the old C8 on steroids rather than the C8 +. As for the latter, the light meter shows that the M21A SST40 is somewhere 10% brighter in hotspot.

Device can’t measure sidelight, but it is definitely brighter. Given the latter, it is precisely that M21A it is more convenient than the C8 + in the near-medium range. Not really, but ok. Of course, S2 + \ S11 \ M3 will be more convenient here, but M21 is clearly better than C8 +.

Throw of both models at maximum brightness I find comparable, of course due to the fact that Convoy M21A is radically brighter than C8 +, as I wrote above at the same brightness C8 + will have better throw , which is not surprising.

Well, let’s see how the Convoy M21A SST40 shines live. In general, mode spacing is not bad, but I would add something in between between 3-40% (which I will offer Simon)

0.1% – gives some kind of light at a distance of up to 5 meters. By and large, this is the same firefly, convenient so as not to hit the night vision and not to bother anyone.

3% – quite a fair runway light, which is visible even at a distance of half a hundred meters. Practical

40% is bright mode. More than sufficient from the position of the close range need, it is better in a situation when you need to work at a distance of 50-100 meters.

100% – there is no point in using it closer than 30 meters. Bright and good breakdown power mode. Not from the category of super-long-range lights, no. Just a little farther c8 + and with a brighter sidelight. Below it is clearly visible in the photo from a distance of 75m.

Well, see for yourself.

7 meters, an absolutely excessive distance for such a flashlight ..


20 meters is also too close for 100%



Here is a small announcement, soon there will be a comparison of the Convoy L21A SST40 and Convoy L21A XHP35. This is a relatively compact long-throwers, essentially known to all L2, only with other LEDs.

Now I will show the difference in light between the Convoy M21A SST40 and the Convoy L21A SST40. On my channel i was asked a question about how they shine relative to each other, nevertheless, with different body sizes, the LED they have is the same. Here, look. L21A SST40 gives a more focused and long-range beam, which is not surprising, in general.


And here are the relevant distances.



400m is already a real useful range. That is, of course, you get a relatively good light (excellent for the price) and it will be very long at one brightness. But for serious work at such and greater distances, you will most likely need to buy some more powerful modern LED flashlight with aliexpress. In the near future we will see if the L21A in both versions will cope with this task.

Of course, the video has a lot more examples of how the Convoy M21A SST shines.


The price tag of the Convoy M21A SST40 is very modest, a little more than the same C8 +. The rest in this Convoy novelty can also be laveled as “little more”: size, throw, battery capacity (well, likely “more” than “little). Only brightness is significantly higher
In general, this model left me with the impression of a more overclocked and well-stabilized good olde Convoy C8 with more capacious battery.

A kind of specific flashlight, something between a mid-range and a long-range. If you sensibly assess your needs and are looking for something with just such a light and for such a distance, then I think that it will not disappoint you.

Regarding the same C8 + there are advantages and disadvantages.

+ Support for a radically more capacious 21700 battery
+ long range at maximum
+ better sidelight at the same brightness as C8 +
+ full stabilization without a drawdown in brightness
+ thermostepdown

- worse range at the same brightness as C8 +
- only 4 brightness levels
- a gap between 3% and 40%.

Edited by: Lumeniac on 04/11/2020 - 03:50
Mocarny's picture
Last seen: 11 hours 9 min ago
Joined: 05/10/2019 - 04:03
Posts: 293
Location: Poland

Nice review and beamshots, thanks Smile

If you struggle choosing your perfect headlamp, check my headlamp guide, I compared 15 most popular headlamps there: CLICK

Last seen: 23 hours 51 min ago
Joined: 04/13/2019 - 11:43
Posts: 113
Location: Hungary

Any recommended 21700 battery?

Red Vapcell INR21700 4500mAh does not fit. I think this was even discussed in the Convoy seller’s topic.

Yokiamy's picture
Last seen: 8 hours 34 min ago
Joined: 10/18/2016 - 15:47
Posts: 2667
Location: Netherlands

Samsung 40T or 50E

Last seen: 17 hours 30 min ago
Joined: 06/02/2013 - 16:56
Posts: 1036
Location: France
I did not have the opportunity to compare them live, but I’m sure that there will not be that difference in brightness that would justify the purchase of a version with cold light.

Yes they are of the same brightness bin so its the same but just a cooler light. Great review!

Last seen: 1 week 4 days ago
Joined: 12/27/2019 - 17:16
Posts: 68
Location: USA

Hmmmm, doesn’t sound like you are that excited for the M21A over the C8+. Currently you can get the C8+ SST40 for about $18 and the M21A SST40 for $22 (with coupon codes). Wondering if the $4 more for the M21A is worth the difference. Anyone have any thoughts on this? Well, besides the likely recommendation to buy both at those prices Big Smile .