Fireflies ROT66 Flashlight Review

Official Specs
Short Review
Long Review
  What's Included
  Manual and Packaging
  Build Quality and Durability
  User Interface and Operation
  LED and beam
  Tint vs...
  Beamshots, Runtime, etc table.
  What I like
  What I don't like
Up Next


Believe it or not, I buy quite a few lights.  More often than not those lights have Nichia emitters.  In this case, the light has nine nichia emitters (and a few other type too).  This light is by a new company on the block who’s hitting quite hard.  This is the FireFlies ROT66.

Official Specs and Features


There are a few versions of this light.  What I have here is the Nichia 219B R9080 in a black body.  There’s also a “Champagne yellow” body.  And quite a few other emitter choices.  All told, there’s this list of choices:

Nichia 219B-V1 R9080 (+$20.00)
XPL Hi V3 1A Cool White (+$30.00)
XPL Hi V3 3A 5000K Neutral White (+$30.00)
SST20 6500K 10W CW
SST20 10W NW 4000K CRI95

It’s also possible to buy the light with cells, and with a driver that isn’t glued in (to allow modding) (and this removes the warranty).

There’s also a version or an add-on with an aux board of secondary emitters.

That’s a lot of choices!


Base price is $78, and the above price modifiers are in effect, per emitter choice.

Short Review

I love no single emitter more than I love the 9080 219b.  Where FireFlies got these, and in such mass, is beyond me but I’m beside myself that they did.  I really, really like this light.  The UI is great too; Andúril, by ToyKeeper.

Long Review

What’s Included

  • FireFlies ROT66
  • Nylon carry pouch
  • Spare o-rings (2)
  • Manual


Package and Manual

The ROT66 ships in a nicely appointed thick cardboard box, with a flip open lid.  There’s a good photo of the light on the front, but otherwise not much printing

The emitter choice is noted with a sticker and handwritten text.


The light and parts are held in place with some custom foam.


Build Quality and Disassembly

Aside from having an….unusual…. look and proportion for a flashlight, this light has fairly good build quality.  I have no real complaints about the build.


The bezel and tailcap are quite distinctive on the ROT66.  My copy has aluminum, but at some point stainless steel has been available (though, doesn’t seem to be mentioned on the product page now).

The body doesn’t have knurling, but just simply some ridges for grip.  Coupled with the grippy anodizing, the overall grip is sufficient.


The parts separate as follows.  The tailcap is dumb, no electronics at all.  In fact it’s not even a conductor in this case, since positive and negative both travel through one end of the cell carrier (this makes the cell carrier directional).


The threads on both ends of the tube are anodized, and it’s thus possible to lock the light out manually.  These threads are frustratingly fine, and coupled with the chalky anodizing and lack of lube, are loud to screw.

While these divots in the retaining ring of the head give the appearance of being easy to disassemble, in fact the parts are glued in.  It’s possible to order a ROT66 without glue, but that means you get no warranty.



Officially 110mm x 49mmx45mm body
Weight: 260gram

This isn’t a huge light.  Bigger than a single 26650 light and smaller than a can light like the Meteor (seen below.)  The ROT66 is a three 18650 light; kind of unusual.

Shorter than a Convoy S2+!



The primary way to carry this light will be the nylon pouch.  I didn’t use that much and failed to get any photos of it.

The other way is a threaded mount.  This is a small threaded mount, which might work on a tripod, but I’m not entirely sure.  It could be a M4 size, but certainly smaller than a light like the Astrolux S43 and Acebeam EC65.



Power is provided by 18650 Li-Ion cells.  The cells live in a 3-cell-capacity holder, which has the positive terminal in the center with a big brass button, and the surrounding is the negative terminal.


There is no electrical connection in the tail end.  This does mean that the carrier is directional.


Completely filled, the holder holds 3 cells.  These cells are in parallel, so the carrier voltage is ~4.2V when filled with fully charged cells.  This also means that the carrier will work with any number of cells, and in any bay.

One thing about this carrier is that it only works with unprotected flat tops, and even then it’s a tight fit.  The HG2’s shown above catch on the positive button when I take the cell out.  The wrapper has started to stretch in those areas.  Just be careful when removing the cell, or have some extra wrappers on hand (both of those things are reasonable things to do when using 18650s anyway.)

Like I said above, both terminals are on one end of this carrier.  That means the cell tube/body/tailcap are not even (technically) needed to run this light.  Of course why would you do that?  but it’s a neat little party trick.  Yes I’m very fun at parties.

Here’s a runtime on Turbo – this is the FET Turbo, too.  The highest of the highest mode.  Turbo steps down very quickly, and I’m seeing around 4000 lumens at a maximum.  At 30 seconds, the output is around 1550 lumens, and the output wiggles from there.  It’s possible to reset the light to Turbo, but this will be largely dependent on your cells ability to deliver tons of current.  The light switches to low (very low) when the voltage gets low.  The light does have LVP, and there’s a set of red emitters in the center (see below) to indicate LV.


Here’s a runtime on the highest regulated mode.  As far as I understand it, this mode doesn’t involve the FET, but is fully regulated by the 7135 chips in the light.  Note that this mode, and what the FET Turbo step down to, are the same level of output.


Here are the low voltage indicating LEDs, in the center of the front of the light.  Strange place for LV indication (if the light’s on are you supposed to look into the light?) but it does work.  I’d love to see these reds used for something else, and the switch to be used for LV warning.

The light should shut down completely at 2.7V or so.  Good LVP!

User Interface and Operation

There’s one switch on the ROT66.  It’s a side e-switch, with four blue indicating LEDs.  It’s quiet, but very clicky, and the rubber cover is nice and grippy.  There have been two UI’s for this light.  The light was initially released with Narsil by TomE.  Narsil is a fantastic UI, and if you have a ROT with that, then be pleased.

Later (and current) iterations ship with Andúril by ToyKeeper.  Andúril is a fantastic UI, and if you have a ROT with that, then be pleased!

My ROT has Andúril, and so that’s what I’ll focus on here.  I’ve had (and reviewed) other lights with Narsil, most recently the Sofirn Q8, which you can read more about here.


First off, here’s the UI chart made by ToyKeeper herself.


Here’s a UI table!

State Action Result
Off Hold On (Low)
Off Click On (Mode Memory)
Off Click 2x Highest Hybrid Mode
Off Click 3x Blinkie Mode Group
Off Click 4x Lockout
Off Click 5x Momentary
Off Click 6x Muggle
Off Click, Click, Hold Strobe Group (Mode Memory Strobe)
Strobe Group Click 2x Strobe Cycle (Candle > Bike Flasher > Party Strobe > Tactical Strobe > Lightning Storm)
Blinkie Mode Group Click 2x Blinke Cycle (Sunset > Beacon > TempCheck > BattCheck)
On Click 3x Switch between Stepped and Smooth Ramp
On Click 4x Ramp Configuration
TempCheck Click 4x Thermal Configuration
Beacon Click 4x Beacon Configuration
Lockout Click 4x Off
Strobe Group Click Off
(Basically) On Click Off
Candle Click 3x 30 minute timer to off
Strobe Group Hold Heighten selected mode (Make faster or brighter)
Strobe Group Click, Hold Lessen selected mode (Make slower or dimmer)
On Click 2x FET Turbo
Ramp Configuration [Wait for Single flash] Click N time for level N. Selection of the “Low” you like best by clicking 1, 2, 3, etc. where 1, 2, 3, etc are different levels of low.
Ramp Configuration [Wait for Second flash] Click N time for 1+Turbo-N. Selection of the “Ceiling” you like best by clicking 1, 2, 3, etc. where 1, 2, 3, etc are different Ceiling levels.
Ramp Configuration [Wait for Third flash] Click for how many steps you want in Stepped mode. Sets Number of Steps.
Thermal Configuration [Wait for First flash] Click for N times for N degrees C. Displays Current Temperature.
Thermal Configuration [Wait for Second flash] Click for N times for 30C + N. Sets Temperature Limit.
Beacon Configuration [Wait for First flash] Click for N times N seconds per flash Sets Beacon Speed.

This is a first pass on a table for Andúril, and I have no doubt it’s incomplete.  But it’s also probably the longest UI table I’ve done, which highlights the versatility of this UI.  There’s definitely some programming levels that aren’t on the table.


Mode Mode Claimed Output (lm) Claimed Runtime Measured Lumens Tailcap Amps
Turbo 5000 4050*/1550 All of the amps
Highest Hybrid (Stepped) 614 1.80
6 (Stepped) 320 0.90
5 (Stepped) 163 0.45
4 (Stepped) 95 0.26
3 (Stepped) 50 0.12
2 (Stepped) 12 0.03
Lowest Hybrid (Stepped)

LED and Beam

The main emitters are the reason to buy this light.  These are Nichia 219b, sw45k r9080 emitters, and there are 9 of them in this light.  That emitter is widely regarded by fanatics as the best for tint, and this one, to quote u/maukka, has a “signature Nichia 219B sw45k rosyness and no artifacts.”  I like this emitter so much it’s the reference emitter in the “Tint vs” section below.


Low is very low.



There are also blue emitters in the switch, and red emitters in the center of the mcpcb.  But these aren’t used for any output levels.

Tint vs BLF-348

The tint isn’t as disparate as this in reality.

Beamshots, Runtime, and Lux Measurements

FireFlies ROT66
Emitter Nichia 219b
Emitter Notes R9080
Cell 18650×3
Runtime Chargetime N/A
LVP? Yes – Warning too
Claimed Lumens (lm) 5000
Lux (Measured) 637 lux @ 5.812 m
Candela (Calculated) in cd 21517.4
Throw (Calculated) (m) 293.4
Throw (Claimed) (m)

Random Comparisons and Competitive Options….

It’s probably reasonable to compare the Noctigon Meteor m43 with the ROT66.  That one’s available with Nichia too, but the current version isn’t the 219b awesomeness.  The beam on the ROT66 is much more useful, too, as it’s not a complete mule.


What I like

  • Nichia 219b r9080
  • UI by ToyKeeper is nice
  • Switch emitters are nice for a kind of a beacon at night
  • Available with other emitters
  • Secondary emitters out the front are a nice touch (even if not seen in this review, I have experienced them first hand and like them a lot).
  • I’ve experienced good customer service from FireFlies

What I don’t like

  • LVW is noted by red emitters OTF of the light
  • Built quality could probably be a little better
  • Switch emitters are under utilized
  • Blue emitters out the front are under utilized (ie no “Off”, no modes, etc)

I like this light enough that it’s my test subject for the SST20 emitters.  I have one with those emitters on order!

Up Next

Not sure what all I’ll have next week, but hopefully I can wrap on some chargers, and a cell review too, among other lights!  And very likely another Fun Fund Friday!


  • This light was provided by no one for review.  I bought this light myself, and I was not paid to write this review.
  • This content originally appeared at  Please visit there for the best experience!
  • Whether or not I have a coupon for this light, I do have a bunch of coupons!!  Have a look at my spreadsheet for those coupons. It’s possible to subscribe and get notifications when the sheet is edited!!

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