In my hands for review today is a small Acebeam AAA light – the M20.  It’s a twisty with good knurling and easy operation; read on for testing!

Official Specs and Features

Here’s a referral link to the official product page.


Just one version, but there are two body colors: black (seen here), and tan.

Price and Coupon

At Going Gear, where I got this review copy, the M20 is $19.90.  I’d recommend you get it at Going Gear!  That’s a shareasale link.  Click through if you’re willing, even if you don’t end up buying.  Clicks help!

Short Review

I like the knurling on this little guy, and the UI is simple and intuitive enough.  I don’t care for the 6500K and XP-G3 is fairly renown as not a favorite emitter.  But at $20, this isn’t a bad gift or keychain light.

Long Review

The Big Table

Acebeam M20
Emitter: Cree XP-G3 (6500K)
Price in USD at publication time: $19.90
Cell: 1xAAA
Turbo Runtime High Runtime
Switch Type: Twisty
On-Board Charging? No
Claimed Lumens (lm) 150
Measured Lumens (at 30s) 151 (100.7% of claim)*
Claimed Throw (m) 50
Candela (Calculated) in cd (at 30s) 37lux @ 3.895m = 561cd
Throw (Calculated) (m) 47.4 (94.8% of claim)*
All my Acebeam reviews!
  • 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

  • Acebeam M20 Flashlight
  • Spare o-rings (2)
  • Springy keychain connector
  • Split ring (attached to light)
  • Manual

Package and Manual

Build Quality and Disassembly

There are a couple of things that stand out about this little AAA twisty right off the bat.  First, the knurling.  It’s diamond cut (my favorite) and is over enough of the body that there’s plenty of grip for twisting with one hand.

Next thing you’ll notice is that the bezel has crenelations, so when headstanding, light will shine out.  Not a big deal but something I like to see.

The two part body has reasonably long threads, and they’re anodized and triangle cut.  Of course when the head is just a tiny bit off the body, the light is mechanically locked out, so no standby drain on the cells.

The tail end has a spring, and the head has a button.  There are two holes in the driver so unscrewing the head should be straightforward for an emitter swap.

The included, attached split ring is nothing to write home about.  Just a wire…. good candidate for replacement.

Size and Comps

Officially 68mm x 14mm (head) x 12mm (body), and 10g (without cell).

Retention and Carry

The included, attached pocket clip is a fairly good one.  The mouth makes for easy attachment to pockets, and it carries deeply enough that the light won’t fall out of a pocket.  It’s a friction fit clip, and has a couple of places to attach a lanyard if you’d like (though I’d attach a lanyard elsewhere).

Also included and also already attached from the factory is this split ring.  It’s nothing special.  It is attached through a hole in the tail end of the light, which adds a good bit of length to the light overall.  I’d rather this be removed altogether (just like on the Surefire Titan Plus).


The pocket clip can be reversed.  It’ll fit on the middle thinnest ring, just left of the Acebeam logo above.  And in this configuration, the M20 may be used on the brim of a hat effectively.

Power and Runtime

Power is provided to the M20 by means of a single AAA sized cell.  Only primary 1.5V max cells are supported – no lithium ion cells (10440).  In my testing exclusively used NiMH cells.

Output goes about as you’d expect.  It’s not very regulated, and just tracks downward as the cell voltage drops.  There is no LVP, but that’s not so bad with NiMH cells.  Output is negligible when cell voltage gets low anyway.  Plus, the emitter flashes in strobe fashion when the voltage is low.  In the graph below, sorry but my thermo probe broke off the light and temperature wasn’t tracked past around 5.5 minutes.  The light is notably hot, though, which is quite interesting.  A temp of 47 degrees in a light this small is something you’d notice.

Output on Medium is remarkably flat and well regulated.  Still no LVP but again the output drops off so fast and dramatically to nearly nothing that you’d notice it.  Also the emitter flashes to alert the user.

Modes and Currents

Mode Mode Claimed Output (lm) Claimed Runtime Measured Lumens Tailcap Amps
High 150 0.8h 151 1.77
Medium 30 4h 25 0.14
Low 2 25h 0.01

Pulse Width Modulation

No PWM on any mode.

For reference, here’s a baseline shot, with all the room lights off and almost nothing hitting the sensor.  And here’s the worst PWM light I have ever owned.  Also one of the very first lights I ordered directly from China!

User Interface and Operation

The M20 is a twisty, so you’ll twist the head to switch modes.  It’s not a progressive twisty – so twist it on, then off and on again to advance modes.  But mode advance is not the normal direction.  Medium is first, then low then High.  The output resets to “Medium is next” after a few seconds.  As a result, High can be completely avoided if desired.

LED and Beam

The emitter in the M20 is a Cree XP-G3 in 6500K temperature.  The reflector is shallow (of course) and has a very light texture.  Not enough to make any flood out of the beam, but just enough to break up any artifacts from the XP-G3.

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

Tint vs BLF-348 (Killzone 219b version)

Test light on the left.

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

Random Comparisons and Competitive Options….

Here’s a link to a relevantly filtered page on  I use that site a lot!  There are indeed a few other XP-G3 AAA lights, but the list is surprisingly short.  This Acebeam makes a good entry in the group.


What I like

  • Knurling and smooth threads make for easy operation
  • Small size
  • Can be used as hatlight
  • No strobes
  • Highest output can be completely avoided

What I don’t like

  • Cree XP-G3, especially 6500K
  • Lack of LVP


  • This light was provided by Going Gear for review. 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 BangGood and GearBest coupons. Please subscribe and get notifications when the sheet is edited!!

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