JETBeam M37 Pro Flashlight Review
The JETBeam M37 Pro flashlight uses a Cree XHP50.3 HI (high intensity) and smooth reflector for great output and good throw. And it has built-in USB-C charging!
Official Specs and Features
Here’s a link to the JETBeam M37 Pro flashlight product page at flashlightgo.com.
Versions
There’s just one emitter option but two body colors: “grey” (looks black to me) or green (seen here). The kit is available with or without the orange traffic wand.
Price
Without the wand, the JETBeam M37 Pro flashlight sells for $77.99. That price does include the 21700 cell!
What’s Included
- JETBeam M37 Pro flashlight
- 5100mAh 21700
- Charging cable
- Spare o-rings
- Lanyard
- Traffic wand (optional)
- Manual etc
Package and Manual
Build Quality and Disassembly
This JETBeam M37 Pro flashlight is a lot like the M37 Crossbow (non-Pro), which I have reviewed. Many of those features will be similar – the build quality, for example, is still great on this Pro version!
These cooling fins are well-placed.
There’s not an MAO version of the JETBeam M37 Pro flashlight, though – that was certainly a draw of the other M37!
Threads on the tail end are anodized and very smooth.
When removing the tailcap (which you may never really have to do, since there’s built-in charging), the pocket clip really does get in the way. During testing (since I have to check cell voltage often), I just removed the pocket clip altogether.
Size and Comps
Size: 147.8mm x 38.5mm x 27.5mm
Weight: 350g
If the flashlight will headstand, I’ll show it here (usually the third photo). If the flashlight will tailstand, I’ll also show that (usually in the fourth photo).
Here’s the test light with the venerable Convoy S2+. The version below is a custom laser-engraved Convoy S2+ host by GadgetConnections.com. I did a full post on an engraved orange host right here! Or go straight to GadgetConnections.com to buy your Convoy S2+ now!
Also above is the light beside a TorchLAB BOSS 35, an 18350 light. I reviewed the aluminum version of that light in both 35 and 70 formats. I also reviewed that specific edition, the “Oveready BOSS FT Collector Vintage Brass” 35. I love it!
I just realized I should have photographed the JETBeam M37 Pro flashlight beside the non-Pro M37. The Pro is bigger in every dimension! Of course, that’s reasonable since this Pro light runs one 21700 and that non-Pro light runs one 18650!
Retention and Carry
JETBeam includes a pocket clip in the M37 Pro Crossbow flashlight package. The clip is a collar style clip, a style that inarguably offers the most sure retention.
The clip fits onto the body “under” the tailcap but can also be placed higher up, for deeper carry. To do that, unscrew the bit surrounding the screw (as seen way up top) and put the clip there. Fit is the same either way. The clip only allows bezel-down carry, though, and is not a two-way clip.
The rubber tactical grip is included and installed by default. It’s soft enough that (once you remove the pocket clip), you can remove it easily too.
A lanyard is also included. It’s most reasonable to attach it through one of the sets of two holes in the tailcap, but you could also attach it to the pocket clip.
Power and Runtime
Included with the JETBeam M37 Pro flashlight is a single 21700 cell. It’s a button top cell, with a rated capacity of 5100mAh.
The cell goes into the light in the usual way – cell positive end toward the head of the light.
Below you can see a couple of runtime tests.
Charging
The JETBeam M37 Pro flashlight has built-in charging.
A USB-C port is hidden behind this collar. It’s a very safe way to cover the charging port!
A USB to USB-C charging cable is included. It’s short!
Charging seems fine but the graph looks weird. I will look at this again – I did not have luck charging C to C but that could be due to the switch setting. The light seems to charge with the mechanical tail switch on or off but charges better with the switch on. The light is not on in that case. So I’ll double-check C to C with switch off and on to confirm. Either way, JETBeam includes an A to C cable (not C to C), so that’s what you should expect to work (and it does).
I think in both of those tests above, the switch was in the off position (which could explain the dropouts). Note that the manual does not state that the light should be either way for charging.
Modes and Currents
| Mode | Mode Claimed Output (lm) | Claimed Runtime | Measured Lumens | Tailcap Amps |
|---|---|---|---|---|
| High | 3700 | 2.2h | 2610 (0s) 2514 (30s) |
11.37 |
| Medium | 450 | 5.6h | 359 (0s) 354 (30s) |
0.65 |
| Low | 30 | 66h | 30 | 0.04 |
Just look at all that room between Medium and High for an extra mode!
Pulse Width Modulation
None of the three official modes use PWM.
Here you can see a “baseline” – a chart with almost no light hitting the sensor. Then there’s the Ultrafire WF-602C flashlight, which has some of the worst PWM I’ve seen. It’s so bad that I used a post about it to explain PWM! Here are multiple timescales (10ms, 5ms, 2ms, 1ms, 0.5ms, 0.2ms) to make comparing this “worst” PWM light to the test light easier. That post also explains why I didn’t test the WF-602C at the usual 50us scale.
User Interface and Operation
The JETBeam M37 Pro flashlight is controlled by one switch. It’s a tail mechanical forward clicky switch.
The button protrudes just a bit too much for tailstanding.
Action on the switch is nice and stiff, which seems suitable for a tactical light of sorts.
Here’s a user interface table!
| State | Action | Result |
|---|---|---|
| Off | Click | High (or low if modes are reversed in settings) |
| Off | Tap | Momentary High (or low if modes are reversed in settings) |
| Off | Repeated Taps (within 2 seconds) | Mode advance (High > Medium > Low) (or LMH if modes are reversed in settings) |
| Off | Double Tap | Strobe |
| On | Click | Off |
| Off | Tap 5x+ then hold (not click) | Mode cycle then momentary and the light will blink 3x to indicate mode selection direction change (HML to LMH) |
LED and Beam
JETBeam uses a Cree XHP50.3 HI emitter in the M37 Pro flashlight. That emitter is coupled with a deep and smooth reflector.
The resulting beam has a tight beam shape. Below you can see a bonus feature: glass-breaking ball bearings!
JETBeam included this orange traffic want in my kit. It’s neat.
I like that the top of the wand is open – you can get a very tight beam with not too much annoying spill this way!
LED Color Report (CRI and CCT)
CCT is neutral to cool, and really fairly pleasant. On high, the light tops out under 5500K. Not bad! CRI is low and the Duv is (very?) positive, though.
Beamshots
These beamshots always have the following settings: f8, ISO100, 0.3s shutter, and manual 5000K exposure. These photos are taken at floor level, and the beam hits the ceiling around 9 feet away.
Tint vs BLF-348 (KillzoneFlashlights.com 219b version) (affiliate link)
I keep the test flashlight on the left and the BLF-348 reference flashlight on the right. These photos are taken around 18 inches from the door.
I compare everything to the KillzoneFlashlights.com 219b BLF-348 because it’s inexpensive and has the best tint!
Summary and Conclusion
This JETBeam M37 Pro flashlight seems like a worthy “Pro” version of the other M37 Crossbow. It uses a cell with higher capacity in a “not much bigger” package. Built-in USB-C charging is a nice bonus, and the cost isn’t outrageous. I appreciate the emitter not being super cool white. Build quality is very good, too!
The Big Table
| JETBeam M37 Pro flashlight | |
|---|---|
| Emitter: | Cree XHP50.3 HI |
| Price in USD at publication time: | $77.99 |
| Cell: | 1×21700 |
| Runtime Graphs | |
| LVP? | Yes |
| Switch Type: | Mechanical |
| On-Board Charging? | Yes |
| Charge Port Type: | USB-C |
| Charge Graph | |
| Power off Charge Port | No |
| Claimed Lumens (lm) | 3700 |
| Measured Lumens (at 30s) | 2514 (67.9% of claim)^ |
| Candela per Lumen | |
| Claimed Throw (m) | 465 |
| Candela (Calculated) in cd (at 30s) | 1815lux @ 5.589m = 56695cd |
| Throw (Calculated) (m) | 476.2 (102.4% of claim)^ |
| Claimed CCT | – |
| Measured CCT Range (K) | 5000-5400 Kelvin |
| Item provided for review by: | flashlightgo.com |
| All my JETBeam reviews! | |
^ Measurement disclaimer: Testing flashlights is my hobby. I use hobbyist-level equipment for testing, including some I made myself. Try not to get buried in the details of manufacturer specifications versus measurements recorded here; A certain amount of difference (say, 10 or 15%) is perfectly reasonable.
What I like
- Neutral(ish) CCT
- Built-in USB-C charging (better than having to fight with the pocket clip over the tactical ring, at least)
- Modes can be reversed
- No mode memory
- Nice firm switch
What I don’t like
- Low CRI
- Positive Duv (greenish beam)
Notes
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