FocusWorks Eryx F1 Flashlight Review

FocusWorks Eryx F1 Flashlight Review

The FocusWorks Eryx F1 is an unusual flashlight with “dragon skin” finish on the body. Titanium and copper parts make this a pretty light!

Official Specs and Features

Here’s a link to the FocusWorks Eryx F1 Flashlight product page.


Internally all the versions of this light are the same.  But have a look at the light and note there are “four parts” – each of those parts is available in copper or titanium, in just about any mix you’d want.  They aren’t always available for sale, but every combo has been made at some point.  In fact, these are generally not for sale, because they’re small-batch, and sell out immediately upon release.


The list price for this light is $650.  The initial release was around $500, I believe.

Short Review

This is such an interesting light.  There’s a ton of copper, and with the H17fx, that’s a good choice.  The titanium is like nothing I’ve ever seen in a light before – the milling is quite unusual.  I like the light.  I’m not sure how much I’ll carry the light, but it really is exquisite.

Long Review

The Big Table

FocusWorks Eryx F1
Emitter: Nichia 219c (4000k 90+CRI )
Price in USD at publication time: $650.00
Cell: 18350
Turbo Runtime High Runtime
LVP? Soft
Switch Type: Mechanical
On-Board Charging? No
Claimed Lumens (lm)
Measured Lumens (at 30s) 619^
Claimed Throw (m)
Candela (Calculated) in cd (at 30s) 135lux @ 5.927m = 4742cd
Throw (Calculated) (m) 137.7^
All my FocusWorks reviews!

^ Standard measurement disclaimer:  I am an amateur flashlight reviewer.  I don’t have $10,000 or even $1,000 worth of testing equipment.  I test output and such in PVC tubes!!  Please consider claims within 10% of what I measure to be perfectly reasonable (accurate, even).

What’s Included

  • FocusWorks Eryx F1 Flashlight
  • Cloth carry pouch
  • Card with flashlight information
  • Stickers (2)

Package and Manual

The light ships in a nondescript box, and there’s no “package” except the cloth pouch.  I’d consider the authenticity card to be part of the package.  I think this card should be kept (even if you don’t normally keep boxes etc) and I think all custom* makers should do this kind of info card.

There also is no manual – driver info is available everywhere since this is a common driver.

Build Quality and Disassembly

Just drink that in.

That right there is something you’ve never seen before in a flashlight.  It’s very hard to describe the barrel of this light.  It’s grippy like knurling but is in no way made like knurling.  It feels more like dragon scales.  And I should know, I grew up with a dragon, and I have vast experience in this area.

Aside from the scales, note the titanium and copper mix.  There are full copper and full titanium versions available, but this version is probably the best mix (opinion, of course).  The copper below the head is needful for dissipating the heat from the 219c emitter!

Attention to detail abounds here: there’s a very subtle FocusWorks logo on the tail end, just opposite the clip.

The tail has a spring and a McClicky switch.  The head has a brass button, and the driver parts can be seen.

The threads on all parts are fairly fine, and triangle cut.  There’s lube on all threads.  It’s thick lube, and there isn’t much of it (both are good things.)

The titanium and copper thread together very nicely.  In fact, copper on titanium is probably the best of all worlds, since there are absolutely zero “grainy titanium” threads.

Here’s a minimal teardown.  I didn’t remove the actual pill – actually not sure precisely how to get the right kind of grip on there to do so….

And here’s a shot with the tailcap removed too.  Removing the tailcap won’t be the primary way to swap cells:  When twisting the tailcap off, the pocket clip rubs the higher points on the body.

The tailcap is all copper, too.

You really should see how this tube is made:

Talk about labor intensive!!!

The cell tube is not reversible.  The internal diameter is different on each end.

There is really a lot of copper in this light!

The driver isn’t held down into the pill by anything, but the copper heatsink will keep it in place properly.

DrJones driver!  The H17fx.

Size and Comps

I don’t see any official measurements for this light, so I’ll posit some myself.

Head diameter: 29mm
Body diameter: 24.5mm
Length: 99.56mm
Diameter at clip: 28.26mm

I weight it at 188.14g.

This isn’t a small 18350 light, in any dimensions.  However, that’s acceptable because it’s a reflector 18350 light.  So the head has to be longer, to allow the reflector to have some depth.  It could probably be argued that the light is overall a little thick.

Not at all a bad size in hand, though.

Retention and Carry

The light ships in a cloth button close pouch, with the Eryx branding.  It’s a good protective pouch, but not something I’ll likely carry the light in.

The main way to EDC the light is the pocket clip, which attaches to the tail with two Allen screws.  This is one of those “cut” clips, not a stamped steel clip.

It’s quite rigid.  Coupled with the texture of the body, you may have to spread open the mouth of the clip in order to get the light onto your pocket.

The clip isn’t bent – it’s cut into the “usual” pattern.  The mouth isn’t very big

Like most lights in this category, the clip screw holes go completely through the tail.  The screws don’t, though.

Power and Runtime

The F1 is powered by a single 18350 cell.  A cell is not included, and I tested with a couple of different cells.  The cell will be of utmost importance to your use of the light, since the DrJones H17fx is a FET on the highest mode, and will make full use of the current a cell can provide.

A flat or button-top cell will work.  Protected or unprotected will work, too, but a flat top unprotected cell is going to be your best option.

The cell can be placed into the light from head or tail, but as I said above, tail removal will not be the best choice due to how the clip hits the higher spots of the body.  Also when you’re changing the cell make sure it’s the body tube you’re removing from the head, and not the cooling fins being removed from the head.  The parts aren’t bound together (which is good!)

I performed two runtime tests.  The first is all default settings and on the highest output.  It’s unclear what the default H17fx setting is, but I don’t believe it’s “Mode 24” which is the absolute full max the driver is capable of.

Then I tested the light after having programmed the highest mode to be the actual highest mode – Mode 24 in the H17fx.  Output was indeed notably higher; over 100 lumens more at 30s.  I did use a different cell, but both are quite capable cells.

Both runtimes didn’t really exhibit LVP, but the light steps down so dramatically that you’ll be aware it’s time to swap cells.

Pulse Width Modulation

PWM is a known entity on the H17f driver, and it’s a complete nonissue. It’s shown here as a matter of course.

For reference, here’s a baseline shot, with all the room lights off and almost nothing hitting the sensor.

User Interface and Operation

The switch is a forward clicky mechanical switch.  This means it’s possible to use the switch as a momentary switch.  It’s big, clicky, and the rubber boot has Prometheus branding.

I will note that the light will tailstand easily – the bezel around the switch is tall enough to allow to sit fully flush on a surface.

I don’t have a UI table for you, but I do have a flow chart that was made for another H17f light, and is applicable for the Eryx F1 too:

LED and Beam

The emitter of choice in the Eryx is a Nichia 219c.  I am a huge Nichia fanboy, and I’m pleased to have one as the default option in this light.

The reflector is another unusual thing – it’s called a “boom” reflector, and has ridges.  The beam profile ends up having a hotspot rolling off all the way to the edges.  Out past the beam, the ridges show up, but it’s more “neat” than “distracting.”

These beamshots are always with the following settings:  f8, ISO100, 0.3s shutter, and manual 5000K exposure.

Tint vs BLF-348 ( 219b version) (affiliate link)

I compare everything to the Killzone 219b BLF-348 because it’s inexpensive, has the best tint, and [probably] still available!


What I like

  • The uniqueness of the build and style
  • A reflector custom!
  • Utilizes a Nichia 219c emitter by default
  • Lots of copper, especially where needed
  • I like that the parts are essentially interchangeable, so a user can ultimately get whatever configuration they want
  • I mean, it’s a gorgeous light.
  • Uses the great DrJones H17f driver

What I don’t like

  • The throw isn’t all that great with the boom reflector
  • Light is heavy and quite big for a 18350 light
  • At $650, this light is quite expensive
  • Pocket clip doesn’t really satisfy my needs as a pocket clip


  • This light was provided by FocusWorks for review. I was not paid to write this review.
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