CMG Reactor3. Rating: 76%


The Reactor3 is the 3AA successor of the highly successful 2AA Reactor released by CMG Equipment a couple of years ago.  The original Reactor featured a white 1 Watt (Low Dome) Luxeon Star LED, and was probably the first affordable flashlight available harnessing the power of the then cutting-edge technology.  The Reactor3 is fundamentally the same light, just lengthened slightly, and running from 3AA Alkaline cells, rather than the 2AA Lithiums the original Reactor preferred (It would run on alks, but at a VERY much reduced output and runtime), this makes the Reactor3 a much more practical light for many applications, as lithium batteries are a little expensive to find in many locations other than the 'net. 

The Reactor3 uses the same unique bidirectional twist switch as the original Reactor (albeit a slightly improved version), a very bright 1W white Luxeon Star LED, the battery tube and tailcap are hard anodized in black (Which makes the Reactor3 a total PAIN to photograph!), the head is polycarbonate, and has a clear lens protecting the LED's optics (Which are of the NX05 type I believe).  The body features some quite aggressive knurling, which does certainly aid in retention of the light when wearing gloves or if your hands are wet (also helps a lot when turning the light on or off one handed), and some rings around the circumference of the body - these don't really appear to serve any functional purpose, but do look nice.  The light is sealed at the tailcap with an o-ring, and as the packaging states that the light is water resistant, I assume is inside the head as well, though I cannot disassemble the head to confirm this.  It isn't a dive light (so don't go diving with it), but should do just fine in the rain.

Fit and finish are good for a relatively low priced mass-market light, and a set of Duracell batteries are included in the packing, so you're good to go right from the start, so on to the review itself.

Product Info:

Manufacturer: CMG Equipment.  Website

Available from: (And various other places)

Price (Correct at time of writing): US $34.95 (20.50).

Size: 20.2 x 3cm (at widest point, and including lanyard loop on tailcap).

Number of lamps: 1.

Lamp Type: 1.2W Luxeon Star LED (Low Dome).

Lamp Current: 235mA.

Lamp Colour: White.

Body finishes available: Black, Hard anodize. 


Switch Type: Unique bidirectional twist head on/off.

Water Resistance: Water resistant, not submersible.

Approximate Beam angle: ~20 Degrees.

Notes: Some earlier model Reactors had occasional problems with the switch, these problems have been reportedly solved with all new units.

Beamshot below taken from 1 metre with colour balance set to "Daylight" - Image appears somewhat more blue than it is in reality.


The Reactor3 comes in an easy to open plastic clamshell pack with a distinctive orange colour scheme.  There are two poppers moulded into the top of the pack, which hold the front and back together, simple pull them apart, and the pack folds open, allowing the packing card, Reactor3 and the batteries to be removed, no need to go hunting down scissors, pickaxes or blowtorches as are required to get into some packaging these days.  Detailed images of the packing card can be viewed by clicking the following links: Front Back Inner.

Power Source:

The Reactor 3 AA to give it its full title, as the name suggests, feeds off three AA size cells.  Unlike the original Reactor though, this one prefers Alkalines, in fact, is says in several places on the packaging, that lithium cells must NOT be used, as this may damage the LED.  I have no intention of testing this theory, as I can't afford to replace this thing if I break it.  Three Duracell Alks are supplied with the light though, so you're good to go right from the start, you do have to install them first though.  This however is pretty simple.

Firstly, unscrew the tailcap, the o-ring fits quite snugly, so it might be a little stiff to get started, I'd suggest lubricating it a little with some silicone grease, not too much, just enough to aid in reducing friction.  Once you have the tailcap off, dump out the old cells, into the nearest bin (or if your neighborhood has a recycling program for batteries, store them away for that).  Then place three new alkaline cells in, positive end facing toward the bezel of the light.  Once that's done, just screw the tailcap back on, that's it.  Simple.  Can pretty easily be done in total darkness, provided that you don't drop the tailcap on the floor like I did first time anyway.

I have checked, and the Reactor3 appears to have reverse polarity protection, and simply won't work if you put the batteries in the wrong way around.  This is a good thing, as Luxeon Star LED's don't like being reverse biased, and can be destroyed if they are.  The Reactor3 however worked just fine after I left it for a while with the batteries in backwards (once I turned them back the right way of course).

The  Reactor3 appears to be free from the potentially annoying battery rattle that is common to a lot of lights, it's not a functional problem, but some people find it annoying.  None of it here though, the Reactor3's silent unless shaken REALLY violently, so shouldn't rattle much at all in normal use.

The packaging states the battery life as 20 hours of high brightness, and a total of 100 hours of usable output.  Eigh...think actual testing of this will have to wait until such time as I have equipment to run automated way am I sitting here waiting a hundred hours for it to go out.  I don't see much reason to doubt the 20 hour figure, it sound reasonable enough, though it WILL be considerably dimmer than it started out by that point.

One thing to note here, only for owners of the original Reactor, is that the tailcap for the Reactor and Reactor3, though visibly identical, are not compatible.  The Reactor's one contains naught but a spring, while the Reactor3's contains the LED's protective resistor.  Putting an original Reactor tailcap on a Reactor3, will do one of two things; if you're lucky, increase the brightness quite a bit at the expense of battery life, or if you're unlucky, blow the LED.  Either way, doing so would void the warranty.


As with the original Reactor, the light from the Reactor3 is provided by a 1-watt Low Dome Luxeon Star LED, with the beam focused by what I believe to be an NX05 optic.  The LED is sealed in the light, and as with most LED lights, is not user-replaceable - this is no great problem though, as these LED's have a service life of something like 100'000 hours, the LED in here is very slightly underdriven (rated to 300-350mA, driven here at 235mA on new batteries), so it should reach that target without too much trouble, and will probably well outlast the light itself! 

The image below shows what you see if you look directly into the bezel of the light when it's turned off (looking into the bezel when the light is on is NOT a good idea, and will probably leave you seeing spots for a while afterward if you're foolish enough to try).  The yellow stuff there is what produces a fair amount of the light you see.  "But the light's white..." I hear you say.  And yes, you're right.  The reason that yellow stuff (a phosphor), is there, is that there is no such thing as a commercially available LED die that produces white light on its own.  So, to get white light from a LED, we simply take a blue LED die, and dump a yellow emitting phosphor on top of it.  The phosphor absorbs some of the blue light, and emits it again as yellow light.  Get the balance right, and you get white.  The yellow you see there, is the phosphor covering the blue emitting die of the LED. 

The consistency of colour from one LED to the next leaves a little to be desired with these Low Dome (So called Batwing) emitters, mainly due to how the phosphor is applied; basically a blob being dumped over the top of the die itself.  This usually leads to some parts of the die having more phosphor than others, and an uneven colour output being produced as a result.  The optics used to focus the beam in flashlights like to magnify these imperfections unfortunately, so if you get a slightly uneven LED, you can get some really weird looking yellow, green and blue artifacts in the produced beam.  It's still somewhat a case of pot luck as to whether a Low Dome Luxeon Star LED is going to have a smooth beam or not, and this has gained the term the "Luxeon Lottery" thanks to someone on Candlepower Forums.  LumiLEDs (manufacturers of the Luxeon Star) are working on this problem all the time though, and things are certainly a good deal better than they were 12 months ago. 

It is due to this phosphor deposition issue, that most lights using the Low Dome emitters, tend to have a greenish tint to the beam as a whole, or the edges.  This light is no exception, though it is one of the better that I have seen.  As the image to the left shows, the beam colour shifts noticeably towards the yellow end of the spectrum, away from the almost pure HID-like white of the main part of the beam.  Though no different to the eye, the camera seems to see this better at a distance, and the image below right, taken from 5 metres away (the furthest I can get from anything inside), shows this quite well.  The green/yellow tint is not actually quite that severe, the camera just sees it that way.  From 5 metres though, that is about how bright the light appears to the eye though.  This light has a very good combination of throw and sidespill, making it almost the perfect type of light for walking around with, inside or out.  Outside was where other (Non LS) LED lights tended to fall down a bit, as they have very little ability to throw over distance (Notable exceptions being those using optics such as the Inova X1 to focus the beam at the expense of sidespill), the Reactor3 makes up for having quite a wide beam though by the sheer amount of light that it put out.

Speaking of sheer amount of light output, the image to the left here, shows the Reactor3 shining on the ceiling next to my Nuwai At-100, which was previously my brightest LED light.  Also shows a slightly better representation of beam colour.    In this case, a pure, almost HID like white in the centre, fading out to a somewhat yellowish outer corona.

At the beam centre from 1 foot, the camera's photometer shows the Reactor3 at 480, and the AT-100 at 285.  I doubt that these are standard units, but it's a comparison if nothing else.


The switch on the Reactor3 is unlike any that I've encountered before.  When you think of a twist on/off switch, you think of either loosening or tightening the head to turn the light on or off...not this one! 

To turn the light on, simply turn the head either way until the light comes on, and it "clicks" into the on detent, this click is both tactile and slightly audible, and can be felt through moderately thick gloves.  The action is stiff enough that it isn't likely to come on if packed in a bag or carried in a pocket, though the light is a little on the long side to be pocketed...though I guess you could have really big pockets.  It'd suit a belt holster quite well too.  Turning the light off again is simply a matter of turning the bezel another "click" until it locks in that position...again, turning either way.  If you keep turning, the light will just turn on, then off, then on, then off, and keep turning...

The early Reactors apparently had a few problems with this switch, units which flickered, or refused to turn on at all; CMG now appear to have addressed and solved these problems with all new Reactors.  Mine doesn't seem to have any problems, even after a few hundred operations, and a few trips the floor.  Should you have any trouble though, the Reactor3 has a limited lifetime warranty, and CMG customer service have a good reputation.

It's a little tricky to switch on or off one handed, that is probably my one and only grumble about the light.  It can be done, but is a bit stiff, and would be near impossible if your hands were weak or cold.


Most of you who have used a large number of lights will by now have discovered that there are some form factors that feel "just right" in the hand.  To me, this is one of them.  This head always looked a bit oversized on the original Reactor, and the body too short.  The same head though on the Reactor3, looks just right, and feels just right.  It's nicely balanced (can be balanced on a finger if you hold it about 1.5cm behind the head), and the knurling is very, very grippy.  The only drawback with this is the fact that if it is carried in a pocket, it picks up bits of fluff and dust like a magnet does iron filings!  As the image to the right shows...those little white specs weren't there five minutes before I took that picture...Still, it serves its purpose very well, and makes retention of the light dead easy, even if your hands were wet or greasy, it's possibly the best performing bit of knurling I've encountered thus far actually.  There are also ribs moulded into the back of the head to aid in gripping it if you had wet or greasy hands.  And in the tailcap, there's a decent sized hole to which you could attach a neck lanyard or other retention device.  Because it's moulded into the aluminium of the tailcap, you don't need to worry about it getting pulled off if you catch it on anything with a strap or lanyard attached.  The light has a noticeable weight to it, feeling nice and solid in the hand, without feeling overly heavy.  It wouldn't become a chore to carry, even after an extended period of time, and the barrel's a nice diameter, not finger-cramp inducing as I find that some of the larger lights can be.


Oops...I kinda already covered this in the lamps section didn't I.

Well, we've all done this before, haven't we.  What's the first thing that you always do when you get a new light?  Yep, look down the barrel and throw the switch.  Do that with the Reactor3, and you'll be in for a rather rude surprise if you haven't encountered an LS based light before - and you probably won't see so well for a while after either.  By LED standards, this sucker is really very bright.  Easily outshining a light which has ten bright 5mm LED's, and managing to do so while having more throw, and better smoother sidespill light as well!  It will certainly be interesting to see how the LS continues to evolve, now that it is actually starting to show up in more mainstream applications and flashlights.  It's amazing how much light that this thing throws out, especially given that people keep mistaking it for a 2AA MagLite (Heck, it's a whole AA battery's length longer!), excellent "Wow Factor" with this.  That odd looking optic really does an excellent job of pointing every photon in the right direction.  Just a shame that the colour isn't as even as it could be.  Personally, the slight green tinge at the edge of the beam isn't really an issue, and it's only visible really is the light's shone onto a white surface from a reasonable difference, doesn't affect practical use at all.  In time, I'm sure that CMG will probably switch to using the High Dome version of the Luxeon Star emitter, which suffers to a far lesser extent from this problem due to the more refined manner used to deposit the phosphor on the LED's die.  Overall, the Reactor3 though, does exactly what is set out to do, in a very, very satisfactory manner.  It's bright, battery life's excellent, and it uses cheap, easy to find batteries.  Excellent.

Durability Department:

The Reactor3 seems to be a very durable instrument throughout.  The body itself is constructed of aluminium, and is unless my eyes deceive me, just over 1mm thick throughout.  The head is made from polycarbonate, which has proved its worth in terms of durability in various places now, and has an aluminium ring around the bezel to help protect the polycarbonate head should it get dropped head-first.  The LED's optic - probably the single most fragile component of the light, is nicely protected behind a clear plastic (quite likely polycarbonate as well) lens.  The lens itself is set deeply enough in the bezel that it should be safe enough from scratches in general use, though it might suffer a little if left rolling around in a busy toolbox or something.  Even if it did become scratched, it would have to be pretty bad before it would get to the stage of actually detracting from beam quality.  The aluminium part of the body has a glossy black hard anodize finish, which is considerably more tough than paint and other finishes, so the body should stay scratch free for a good time, even if used in pretty harsh conditions.  My main concerns on the durability, have to lie with the head and the switch.  Though strong, polycarbonate isn't as tough as aluminium, and will pick up scratches more easily.  It did however survive being beaten against the side of my desk repeatedly, and being thrown across the room, shrugging that abuse off with sheer impunity, without even flickering.  Despite the fact that it sometimes makes some scary sounding plasticy snapping noises if you take a firm hold of the head in the right place (on the seam between the two halves), I don't think that you're likely to actually break it though.  Then there's the switch; CMG claim to have fixed the occasionally flaky switch of old, on all current model Reactors, and I can't seem to make mine misbehave.  I've beat it against things, spun the switch rapidly through 360 degrees, pulled and pushed on the head and turned it back and forth quickly.  Thus far, not causing any trouble.  I think CMG have fixed it, and that the unique switch should be okay.  Will post it here though should I have any problems with the switch in the future though!

The only other potential durability issue, is weatherproofing.  The Reactor3 claims to be water resistant, and is certainly sealed at the tailcap.  However, suction testing shows that there is some (not much though) air leakage from the head end.  I don't think to an extent that it will be a problem at all in the rain or snow, and the light should survive a brief trip into shallow water okay.  Leave it in there for long though, and I reckon that it would fill up before that long.  Provided the water was clean though, and you got it dried out quickly enough, the Reactor3 would probably survive the ordeal, as there are no fancy electronics in there, how the switch would take the treatment though, I don't know (And I can't afford to find out).


The Reactor3's no Surefire, and it doesn't pretend to be.  Okay, the beam colour could be a little better, the weatherproofing could maybe improved a bit, and the switch mechanism, you either like or hate.  I personally like it.  The Reactor3's a bright, well put together light, which seems durable.  The best selling point here, really has to be the fact that it's an LS based light, at a mid-range LED based price.  Good example of this, is that the Reactor3 shown on this page, is available for US $34.95 Probably less if you keep your eyes open on eBay), while the Nuwai AT-100 (10 5mm LED based light this was compared to for brightness), retails at around $40.  And the Reactor3 outshines the AT-100, and is easier to carry.  Much as I like the AT-100, the Reactor3 would be my choice of the two.  For the money, this is a good light in my opinion.  It's the principle and the good points of the original Reactor's design, with a few of the bugs ironed out.  Good value for money, cheap to run, and excellent for confusing MagLite 2AA owners.




+Potential for excellent battery life.

+Uses cheap and easy to find batteries.

+No bulbs to burn out.

+Innovative idiot-proof switch.



-Beam colour could be a little better.

-Not fully waterproof.

-Cannot use lithium batteries.


>Cannot be stood on tail to light a room by shining on the ceiling.


Beam Quality: 5

Build Quality: 7

Battery Life: 9

Durability: 8

Value: 9

Overall: 38 / 50 = 76%


Long Term Testing:

24.Dec.2003: Updates of any consequence will be posted here.

28.Jan.2004: UPDATE: Measured and added the current delivered to the LED.  235mA with fresh batteries.  Also out of curiosity I measured the current drawn if one was to short circuit the resistor in the tailcap - briefly.  Draws around 700mA, which isn't totally insane in a light with good heatsinking, but in the case of the reactor, would lead to the LED overheating and burning out in a pretty short time.  It is REALLY bright though!  Still, I stand by my decision NOT to bypass the resistor.

No problems to report.

3rd August 2009: Updated page so that it now works on the new server.  This light is one of the ones which is packed away at the moment (I only have so much space!), but was working fine when it was put away.  The flickering issue I've heard so much about doesn't seem to have affected this light.

It's sufficiently obsolete in terms of LED flashlights though that I'm leaving the review up mainly for interest's sake to be honest - wasn't a bad light in its day, but it has been left behind by modern offerings.