eternaLight DERRINGER

eternaLight Derringer, retail $28.40 (
Manufactured by Technology Associates (
Last updated: 03-03-07

LED Light

The eternaLight Derringer is a small, pager-style LED flashlight that features 2 white LEDs and 1 red LED. Instead of just "on" and "off", the Derringer has 13 modes plus off, and all of its modes can be accessed from a single pushbutton on the top of the flashlight's body. It comes in a cute and loveable little translucent red case.

In many ways, it can be compared with other eternaLight models, but it's smaller and less expensive. It uses three AAA cells for power, instead of three AA cells used by other eternaLight models. It has a battery door so you can change the batteries anytime, anywhere without having a phillips screwdriver handy. It has a smaller body, styled after the popular eternaLight Ergo and X-Ray models. The Derringer isn't too water resistant though, so please take care that you don't get it too wet or drop it in water.


Short of writing an instructional manual here, I'll outline the functions for the Derringer, and how to access them.

  1. Timer mode: This is the first mode the Derringer enters when you hold the button down for 2 seconds or more. The two white LEDs will come on right away, so you don't have to wait in order to get light. The red LED will come on for about 3/4 of a second, and then start briefly blinking about once a second in this mode - to let you know you're in timer mode.
    Both white LEDs will stay on at full power for about 5 minutes, then one of them will go out. The remaining lighted one will stay lit for another five minutes, then it too will go out by itself. Pressing and holding down the button for 1/2 a second at any time will turn the Derringer off. Clicking the button very briefly will go to the next mode, "ON-High Mode".

  2. On HIGH Mode: In this mode, both white LEDs will light at 100%, and stay that way until you turn the flashlight off (pressing and holding the button down for 1/2 a second), change modes, or until the batteries poop out.
    Expected battery life ("EBL") in this mode is approximately 25 hours.

  3. On MEDIUM Mode: In this mode, both white LEDs will be on at 33% power, and stay that way until you turn the flashlight off, change modes, or until the batteries poop out.
    EBL is approximately 150 hours.

  4. On LOW-Left Mode: In this mode, the left-hand white LED will come on at around 5%, and stay that way until you turn the Derringer off, change modes, or until the batteries call it quits.
    EBL is approximately 450 hours.

  5. On LOW-Right Mode: Same as the mode above, except that the right-hand white LED comes on at 5% instead of the left-hand one.
    EBL is approximately 450 hours.

  6. On LOW-Red Mode: In this mode, the center (red) LED will come on at 8% power, and stay on until the flashlight is turned off, until the mode is changed, or until the batteries crap out.
    EBL is approximately 400 hours.

  7. On HIGH-Red Mode: In this mode, the red LED is lit at 50% intensity, and stays that way until the light is shut off, until the mode is changed, or until the batteries go to pot.
    EBL is approximately 50 hours.

  8. Beacon/Locator Mode: In this mode, the Derringer will briefly flash its white LEDs about once a second; first one white LED, then the other. Lather, rinse, repeat. It will stay in this mode until it's shut off, until you change modes, or until the batteries die.
    EBL is approximately 1,500 hours.

  9. White Flasher Mode: In this mode, the Derringer will flash its white LEDs at full intensity about 1 time per second. It will stay in this mode until you change modes, until you turn the Derringer off, or until the batteries become pooped out.
    EBL in this mode is approximately 150 hours.

  10. Red Flasher Mode: This mode is the same as the above, except the red LED flashes at full intensity instead of the white ones.
    EBL is approximately 400 hours.

  11. Red/White Flasher Mode: In this mode, the white LEDs and the red LED flash at full intensity, alternately, at about 3Hz. The light will keep flashing like this until you turn it off, change modes, or let the batteries poop out.
    EBL in this mode is approximately 70 hours.

  12. All-On/Battery Check: In this mode, all three LEDs in the Derringer will come on at full power. If the red LED is noticeably brighter than the two whites, the batteries may be weak and may need to be changed. The Derringer will stay in this mode until it's turned off, until you change modes, or until the batteries are totally pooped.
    EBL is approximately 15 hours.

  13. S.O.S. Distress Signal Mode: In this mode, the Derringer automatically flashes the international distress signal (S.O.S.) with three short flashes, three longer flashes, and three short flashes. Lather, rinse, repeat. The Derringer will do this until you turn it off.
    EBL in this mode is approximately 50 hours.

  14. Off: This mode turns the Derringer "off", as you might have expected from its name. Pressing the button for half a second in any mode turns the Derringer off. So you don't have to sit there and f&$# with it or anything like that. ;-)

Like I mentioned already, "EBL" stands for "Expected Battery Life".

You also have a "momentary" mode (for quickly flashing at something or for sending morse code messages). While the Derringer is off, pressing the button for LESS than 2 seconds turns the two white LEDs on at 100% intensity; releasing it to turn them back off. If the button is held down for more than 2 seconds, the Derringer will go into Timer mode, announcing that fact by turning its red LED on for around 3/4 of a second, then winking it briefly around once a second or thereabouts after that. Press the button for more than 1/2 of a second to turn your Derringer back off.

The Derringer comes with a generous opening on its tail end to feed the lanyard of your choice through. A lanyard is not included, so you can use whatever feels right for you if you need to use a lanyard.

Changing the batteries in a Derringer is a tool-free process, unlike other eternaLight products where you need to remove 2 or 4 phillips screws before you can start dumping.

Remove the battery door by pulling back the latch with your fingernail or thumbnail, then swing the door back and remove it.

Remove the three dead AAA cells, and dispose of them as you see fit. Insert new AAA cells in the chambers provided for them, following the polarity markings embossed in the bottom of each chamber. The spring in each chamber goes to the flat (-) negative side of each cell if you can't see the embossings for any reason.

Replace the battery door by placing the back end of it into the space on the flashlight for it, then swing it down until it latches closed with a clicking sound and feel.

See above for estimated battery life to 20% in each mode.

The Derringer seems reasonably sturdy and durable like other eternaLight products. The Derringer is not water resistant though, so if you think it got wet inside, remove the battery door and batteries, and set the light bottom up (so the battery compartment faces up) in a warm (not hot), dry place for at least a day.

The Derringer can be stood up on its tail for "candle" use, but you have to have a flat surface for this to work, otherwise it will probably fall over quite readily (well, most cylindrical barrel type flashlights might fall over under these conditions too).

The Derringer is not very water resistant, so you'll want to keep it away from ponds, rivers, creeks, puddles of dog pee, snowbanks, fishtanks, or other places where water may be found. If your Derringer does get douched inside, remove the battery door and batteries, and leave the flashlight in a warm dry place for a day or two to let it dry out. Hmmm, I said that already, didn't I?
The Derringer is a good (and cute and lovable) little light though, as long as you don't let the dog go to the bathroom on it or throw it in the pool for the kids to go after. Keep it away from water, and it ought to be good to you. You know, never have to change the bulb again, long battery life, cheap & readily available batteries, and horse puckey like that. Things you might have to worry about with a regular flashlight, you won't have to worry about with a Derringer.

The unusual "phaser-like" shape could take some getting used to if you're accustomed to using barrel-style cylindrical flashlights, but adapting to the flat shape shouldn't take that long.

When you pick up a Derringer, your thumb falls right over the switch button. Pushing and using the button is easy, and really isn't tiresome at all.

There's supposed to be "smash protection" logic built in, but I have not yet figured out how it works. I pushed the button and held it down for several minutes, but nothing happened. Since the light comes on in Timer Mode though, it ought to turn itself all the way off after 10 minutes, whether the button is squished down or not.

The beam with the two white LEDs going full blast.
Measures 29,900 mcd.

The beam with the single red LED going at 50% (Mode #7 above). Measures 3,000mcd.

The beam with all three LEDs going full blast.
Measures 34,000mcd.

All beam pictures are at ~12" from the test target.

Spectrographic plot
Spectrometer plot of the red LED in this flashlight.

Spectrographic plot
Spectrometer plot of the white LEDs in this flashlight.
Ocean Optics USB2000 Spectrometer on loan from TWO-CUBED.

ProMetric analysis
Beam cross-sectional analysis (white LEDs).

ProMetric analysis
Beam cross-sectional analysis (red LED).
Images made using the ProMetric System by Radiant Imaging.

UPDATE 02-25-04:
I irradiated the Derringer's red body with a 50mW green laser and a NUV Inova X5T, and observed some fluorescence. This effect was greater with the green laser beam than it was for 5 somewhat overdriven NUV LEDs radiating at around 400nm. I realise this is an issue that will affect very few users of the Derringer (after all, who goes around shining lights on flashlights), but I thought it was worthwhile mentioning.

Sample was received from a website sponsor on 07-29-03, and the page was put up on 08-07-03.


Smaller than other eternaLight models
Good looking, cute and loveable little translucent red case
Tool-free battery change
Uses inexpensive and easy to find batteries


Not very water resistant; not submersible at all
You need to learn its modes and how to access them

    MANUFACTURER: Technology Associates
    PRODUCT TYPE: Handheld LED flashlight
    LAMP TYPE: 5mm LED
    No. OF LAMPS: 2 white, 1 red
    BEAM TYPE: (White) Bluish-white hotspot w/soft falloff. (Red) Ringy, a bit blotchy.
    SWITCH TYPE: Digitally manipulated pushbutton on top of case
    BEZEL: None
    BATTERY: 3x AAA cells
    CURRENT CONSUMPTION: Unknown/unable to measure
    WATER RESISTANT: Very light spash resistance only
    ACCESSORIES: None that I'm aware of
    WARRANTY: 1 year limited


    Star Rating


Do you manufacture or sell an LED flashlight, task light, utility light, or module of some kind? Want to see it tested by a real person, under real working conditions? Do you then want to see how your light did? If you have a sample available for this type of real-world, real-time testing, please contact me at

Please visit this web page for contact information.

Unsolicited flashlights appearing in the mail are welcome, and it will automatically be assumed that you sent it in order to have it tested and evaluated for this site.
Be sure to include contact info or your company website's URL so visitors here will know where to purchase your product.

WHITE 5500-6500K InGaN+phosphor 
ULTRAVIOLET 370-390nm GaN 
BLUE 430nm GaN+SiC
BLUE 450 and 473nm InGaN
BLUE Silicon Carbide
TURQUOISE 495-505nm InGaN
GREEN 525nm InGaN 
YELLOW-GREEN 555-575mn GaAsP & related
YELLOW 585-595nm
AMBER 595-605nm
ORANGE 605-620nm
ORANGISH-RED 620-635nm
RED 640-700nm
INFRARED 700-1300nm
True RGB Full Color LED
Spider (Pirrahna) LEDs
True violet (400-418nm) LEDs
Agilent Barracuda & Prometheus LEDs
Oddball & Miscellaneous LEDs
Programmable RGB LED modules / fixtures
Where to buy these LEDs 
Links to other LED-related websites
The World's First Virtual LED Museum
Legal horse puckey, etc.
LEDSaurus (on-site LED Mini Mart)

This page is a frame from a website.
If you arrived on this page through an outside link,you can get the "full meal deal" by clicking here.