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 :innocent: ). 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”“:https://axiosreviews.com/2021/09/12/convoy-m21b-gt-fc40-review/. 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.
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.)
EDIT 10/20/2024: The M21E with GT-FC40 4500k is one of my most favorite lights because it is small, has Nichia-like tint, and great throw and brightness for a LED with fantastic CRI and tint. It is for me the perfect gift light, every day light, or walk light. I like it so much that I bought a second M21E from Convoy last month. Unfortunately, this second light has greenish beam color that is noticeably and significantly different from my other 3 Convoy lights with the same GT-FC40 4500k LED. A forum member had mentioned this tint lottery problem with this LED to me in the past, and now I could confirm it with first hand experience.
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
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 
. 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.
