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Review of the Keychain Green Laser Module


Active member
Nov 1, 2006
Keychain Green Laser Module, retail $49.95

Manufactured by (Unknown)
Last updated 01-10-11

This is a green DPSS (diode pumped solid state) laser module that fits on your keychain!!! This is, by far, the smallest green beam laser I've come across to date (12-12-05).

It comes in an all-metal body, and feeds from three LR44 button cells - the ubitiquous "laser pointer battery". It's a very hungry laser module though, so it's good that so many extras were included.


To use the laser module, just aim it at something you wish to point out, and press & hold down the button on the barrel for as long as you need the laser spot. Release the button to turn the laser module back off. Yes, it really is as easy as that.

To change the batteries in your green laser module, unscrew and remove the tailcap, and set it aside.
Tip the three used LR44 cells out of the barrel and into your hand, and dispose of or recycle them as you see fit.

Insert three new LR44 cells into the barrel, button-end (-) negative first. This is the opposite of how batteries are installed in most flashlights, so please pay attention to polarity here.

Screw the tailcap back on, and be done with it.

Current usage measures 152mA on the included LR44 button cells.

Published battery life is just ten minutes a set
; it's a good thing that four spare sets are included in addition to the set already installed.

The laser radiation is CW (continuous wave), not pulsed.

Beam photograph at ~12".
Beam is not white like this photograph makes it appear.

Beam is also a lot smaller than it appears; the
beam image bloomed significantly when photographed.

Measures 5.505mW on a laser power meter specifically designed for that purpose.

Beam photograph at ~15'.
Beam is not white like this photograph makes it appear.

Beam is significantly smaller than it appears;
the beam image also bloomed when photographed.

Those rectangular graphic things near the center are marquees from:

Cinematronics ''Star Castle''
Midway ''Omega Race''
Williams ''Robotron: 2084''
Gremlin/Sega ''Astro Blaster''
Atari ''Tempest''
Williams ''Stargate''
Williams ''Joust''
Venture Line ''Looping''
Sega ''Star Trek''
Midway ''Gorf''

upright coin-op arcade video games from the early-1980s.
That red thing is from an American DJ Laser Widow.
I do not have an outdoor laser testing facility at my new location,
so I will not be able to provide any distance photographs.

Spectrographic analysis of this laser.

Spectrographic analysis of this laser; spectrometer's response widened to pinpoint NIR laser line from the pump diode.
As you can see, none is detectable -- this shows that the IR filter in this laser is doing a fantastic job!!!

USB2000 spectrometer graciously donated by P.L.

Test unit was purchased on Ebay on 12-08-05, and was received on the afternoon of 12-12-05.

Because this unit measures just in the CDRH Class IIIb range (5.505mW), I should call it a "module" on this web page, not a "pointer".

UPDATE 01-08-06:
I noticed something rather disturbing a few moments ago (1:11pm PST): as I was looking for the clasp for my keys so I could reattach them to my EDC bag, I noticed the tailcap of this laser had unscrewed itself approximately one turn. This gives the potential loss of the laser if it is not Caught in a Mosh (o o, there I go thinking about the heavy metal band Anthrax again!) - caught in time. For this reason, I have decided to derate it by ½ star.

UPDATE 01-15-06:
I noticed this morning that the metal tip of the laser had become unscrewed and fell off who knows where.
Kiss another ½ star goodbye.

UPDATE 01-15-06:
No, you aren't seeing things.
Yes, a same-day update.
I found the metal tip for the laser outside the back door early this afternoon (12:24pm PST today); I have screwed it back onto the unit so I once again have a whole laser, instead of one missing a part. But I have - for the time being anyway - retired the laser from keychain duty and placed it on the front of my computer keyboard - resting against the sides of the F7, F8, and F9 keys to be specific.

Bright green laser beam.
Smallest green laser I've come across
Feels good in the hand; is also rather hefty.
No beam artifacts - none that I've been able to detect anyway.
Lots of extra cells come with it if you purchase on Ebay

Not waterproof or submersible - but most modules aren't. Will not figure into my rating.
Consumes a lot of power, so you'll be going through batteries if you use it a lot.
Battery lifetime is estimated at just ten minutes a set.
More delicate than directly-injected diode laser pointers/modules.
Just a hair over the Class IIIA limit it is labelled for.
Can become unscrewed and potentially fall off your keychain.

PRODUCT TYPE: Keychain-style laser module
LAMP TYPE: DPSS diode laser/NdYVO4/KTP crystals
BEAM TYPE: Very narrow; it's a laser, remember?

SWITCH TYPE: Pushbutton momentary on/off on barrel
BEZEL: Metal; has aperture (hole) for laser beam to emerge
BATTERY: 3x LR44 button cells
WATER- AND URANATION-RESISTANT: Very light splatter-resistance at maximum

ACCESSORIES: 15 batteries, spring-loaded "lobster claw", split ring, swivel
WARRANTY: Unknown/not stated


Last edited:


New member
Dec 21, 2008
...Last updated 01-10-11... the smallest green beam laser I've come across to date (12-12-05).
Williams ''Robotron: 2084'' ... the IR filter in this laser is doing a fantastic job.... this unit measures just in the CDRH Class IIIb range (5.505mW)...​
Updated 1/11 ... of a 12/05 pointer? what part of the review did you update, exactly?

The idea of a true 552nm 5mW after-IR filter is actually not bad, not bad at all... Of course I hope the price has dropped in 2005... $50 a lot of money now a days for a keychain lazor... :-/

/off topic
p.s. Bezerk was one of my all-time favorite Arcade games and, if I'm not mistaken, the predecessor of Robotron. As for Williams, my all-time favorite game was Defender :bowdown: I have both Defender and Robotron on a Nintendo Gameboy Advance cartridge and occasionally play Defender via a MAME emulation on the PC platform ;)