JETBeam M37 Crossbow Flashlight Review

The JETBeam M37 Crossbow flashlight uses one Cree XHP50.3 and a deep reflector for great throw. The white finish and simple user interface stands out, too!

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Official Specs and Features

Here’s a link to the JETBeam M37 Crossbow flashlight product page at flashlightgo.com.

Versions

Only one emitter is available but the JETBeam M37 Crossbow flashlight body can be had in either white (seen here) or black.

Price

The black body JETBeam M37 Crossbow flashlight sells for $59.99 but the white commands a slight premium, at $65.99. The JETBeam M37 Crossbow flashlight is available now at FlashlightGo.com.

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Short Review

Let me comment on the finish first: this white finish is great. I am not sure I’d call it “micro-arc” (MAO) – it’s more like what Olight uses on their recent white flashlights. That’s actually a good thing – MAO is often fairly fragile. This M37 finish seems a bit more robust. Anyway, it looks fantastic. As for the light itself, I think it’s good but I do not like three-mode drivers (especially HML ones), and the stepdown seems very dramatic. Also, the manual doesn’t cover everything about the light, which is a bit frustrating. But I love the format, and the light looks great.

Long Review

The Big Table

JETBeam M37 Crossbow flashlight
Emitter:	Cree XHP50.3
Price in USD at publication time:	$65.99
Cell:	1×18650
Runtime Graphs
LVP?	Yes
Switch Type:	Mechanical
On-Board Charging?	Yes
Charge Port Type:	USB-C (on cell)
Charge Graph
Power off Charge Port	–
Claimed Lumens (lm)	3000
Measured Lumens (at 30s)	1136 (37.9% of claim)^
Candela per Lumen	11.13
Claimed Throw (m)	340
Candela (Calculated) in cd (at 30s)	778lux @ 6.109m = 29035cd
Throw (Calculated) (m)	340.8 (100.2% of claim)^
Claimed CCT	–
Measured CCT Range (K)	6700-7400 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’s Included

• JETBeam M37 Crossbow flashlight
• JETBeam 3500mAh 18650
• Pocket clip
• Lanyard
• USB to USB-C charging cable
• Spare o-rings (2)
• Manual etc

Package and Manual

 

Build Quality and Disassembly

Check out that white finish! Even aside from the finish, just look at how flashlighty this light is.

Those among you who have been Surefire fans in the past might recognize this square body shape. I don’t think it’s a copy but it does sort of seem to “pay homage to” some Surefire designs of years past. That said, JETBeam has also definitely used this before, too! It’s interesting, but since both the head and tail are round, the square middle doesn’t add any anti-roll features. For example, the JETBeam M64 has a very similar body!

These cooling fins are well-placed.

I didn’t do it but I suppose you could disassemble the head by removing these TORX screws.

The tailcap that surrounds the rubber switch cover also unscrews. More on that later.

JETBeam applies some very fine knurling in the right places, too.

Threads on the tail end are anodized (or “finished” – whatever the finish is).

I really found myself removing the head when accessing the cell, though. This isn’t really the better way, since these threads are unanodized (and therefore less smooth) but they’re short and gripping the light to unscrew here seems easier. The head (and tail, as seen above) both have very beefy springs, as you’d expect from this type of light.

Size and Comps

Size: 143 x 37.5 x 25.5mm
132.5g without battery

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 you see below is an orange Convoy S2+ host that’s been laser engraved by GadgetConnections.com. I did a full post on this light right here! Or go straight to GadgetConnections.com to buy your Convoy S2+ now!

Also above is the light beside a new standard 18350 light! It’s not one I’ve reviewed yet but this is the CWF Arcadian Peanut in aluminum. This one is stonewashed and has the new Quantum Dragon driver – a whole new product! Stay tuned for a full review of this tiny powerhouse!

Retention and Carry

JETBeam includes a pocket clip in the M37 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 clip will mar the white finish. What you can see below is with just minimal usage of installing and removing the clip.

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, too.

Power and Runtime

Included with the JETBeam M37 Crossbow flashlight is a single 18650 cell. It’s a button top cell, with a rated capacity of 3500mAh.

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.

I’m not actually fully satisfied with these graphs, particularly since the “hidden” mode is not tested here. I will likely retest this…

There’s actually another mode that I don’t see mentioned in the manual, and only discovered because I tested the light on a bench power supply. When the light is cycled from High to Medium to Low and then one more mode, that mode is a sort of “Highdium.” Notably it pulls around 2.2A and has around 700 lumen output (which doesn’t match up with the modes mentioned in the manual.) Really this is great – I want four modes. The flip side is that this means the levels are now grossly out of order (High, Medium, Low, Other Medium, Medium, Low is the progression). It also means that the 8+A High (highest) mode is not accessible after the first cycle through the modes!! You have to turn the light off and turn it back on to get back to the very high output!

Charging

The JETBeam M37 Crossbow flashlight has built-in charging. This charging is by way of a USB-C charge port in the positive end of the cell.

A USB to USB-C charging cable is included. It’s short!

I tested USB-C to USB-C, and that works great.

A to C works fine, too.

Modes and Currents

Mode	Mode Claimed Output (lm)	Claimed Runtime	Measured Lumens	Tailcap Amps
High	3000	1.8h	2181 (0s) 1136 (30s)	8.80
Medium	600	2.8h	545	0.83
Low	30	48h	22	0.05
Unstated Mode	–	–	957	2.32

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 Crossbow flashlight is controlled by one switch. It’s a tail mechanical forward clicky switch.

Thanks to the tailcap shape, the light can tailstand flawlessly.

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
Off	Tap	Momentary High
Off	Repeated Taps	Mode advance (High > Medium > Low > (Unstated mode))
Off	Double Tap	Strobe
On	Click	Off

LED and Beam

JETBeam uses a Cree XHP50.3 emitter in the M37 Crossbow flashlight. That emitter is coupled with a deep and orange peel reflector.

The resulting beam has a fairly tight beam shape.

JETBeam added three glass breaking ball bearings in the stainless steel bezel. The bezel on this light is exceptional!

LED Color Report (CRI and CCT)

CCT is very cool white, especially on High. By Low, the CCT has warmed up a bit but only to the 6700K range (still very cool!) CRI is somewhat low, too, but hits around 80.

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.

I compare everything to the KillzoneFlashlights.com 219b BLF-348 because it’s inexpensive and has the best tint!

Conclusion

What I like

• Great white color and finish (the white is more than a color, it’s a feel of surface, too. Hard to explain)
• Very good build quality
• Simple user interface
• Complete package
• Not complicated by onboard charging (but cell offers it)
• Great bezel

What I don’t like

• Huge stepdown on the highest mode
• “Hidden” High mode will be confusing for users
• Very cool white

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Notes

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