Nat. Pen Co. Custom-Engraveable LED Flashlight, retail $1.89 (
Manufactured by (Unknown)
Last updated 10-16-13

This is a lovely-looking keychain flashlight in handsome silver-colored and shiny dark brown lacquer-finished body (body colors are also available in blue, red, and gunmetal).

It has not one, not two, but THREE phosphor white LEDs, which was a bit surprising given the cost ($1.89) and its source (a promotional item), and it feeds those LEDs from a quartet of LR44 button cells (the ubitiquous "laser pointer battery").

It is designed to be custom-engraved (as you see in the above photograph) with your company name, logo, etc. As you can see, the engraving appears to be very professionally done.

The Custom-Engraveable LED Flashlight is specifically intended to be carried around on your keychain, so that you always have a little light just when you need it -- plus the engraving on the barrel is like having free advertising for your business; whomever sees it (either on your keychain or in use) will see your company's name rather clearly. The Custom-Engraveable LED Flashlight is intended to be handed out to customers, placed in the bottom of boxes of other product as a gentle reminder for them to reorder, etc.

 Size of product w/hand to show scale SIZE

To use this flashlight, firmly press & release the black tailcap button to turn it on; repeat the same action to neutralise it.

There is no momentary or signalling mode available when the flashlight is off; however the light may be blinked when it is on by partially holding the tailcap button in (before it clicks). If you can live with the reverse action, you can indeed blink the flashlight this way.

To change the batteries in your spiffy new (or corroded old ) Nat. Pen Co. Custom-Engraveable LED Flashlight, unscrew & remove the tailcap, carry it to a bridge over deep water (the Oakland Bay Bridge would be ideal; however, the Juneau-Douglas Bridge would also do in a pinch here), and throw it over the side so that it goes "blub blub blub" all the way to the bottom of Gastineau Channel with all of the bowling balls that were lobbed over that bridge in the 1950s and 1960s...O WAIT!!! YOU'LL NEED THAT!!! So just set it aside instead.

Tip the used LR44 button cells out of the barrel, and dispose of or recycle them as you see fit.

Slide four new LR44 button cells into the barrel, orienting them so that their nipple-ends (-) negatives go in first.

Screw the tailcap back on - and there, you're done.
Aren't you glad that you didn't throw that tailcap over the side of the Juneau-Douglas Bridge now?

This is what the Juneau-Douglas Bridge looks like...or what it lookED like anyway before it was replaced in 1976.

And this is what the bridge looks like now.

Current usage measures a scant 8.70mA on my DMM's 400mA scale.
That equals just 2.90mA per LED, so they'll have extremely long, comfortable lives in this flashlight.

This is far lower than the current that I've measured on other lights that use button cells, so those itty bitty little things will last far longer than they would in other lights that use the same cell type.

This is a somewhat small flashlight with a plastic barrel, not a flashlight in a sturdier plastic or metal body that was meant to be thrashed, trashed, and abused. So I won't try to drown it in the toliet tank, bash it against a steel rod or against the concrete floor of a carport in effort to try and expose the bare Metalmarineangemon - er - the bare Metaltrailmon - um that's not it either...the bare a sec here...THE BARE METAL (guess I've been watching too much Digimon again! - now I'm just making {vulgar term for feces} up!!!), let my mother's big dog's ghost, her kitties, my kitty or my sister's kitty cat piddle (uranate) on it, hose it down with my mother's gun, run over it with a 450lb Quickie Pulse 6 motorised wheelchair, stomp on it, use a medium ball peen hammer in order to bash it open to check it for candiosity, fire it from the cannoņata, drop it down the top of Mt. Erupto (now I guess I've been watching the TV program "Viva Piņata" too much again - candiosity is usually checked with a laser-type device on a platform with a large readout (located at Piņata Central {aka. "Party Central"}), with a handheld wand that Langston Lickatoad uses, or with a pack-of-cards-sized device that Fergy Fudgehog uses; the cannoņata (also located at Piņata Central) is only used to sshoot piņatas to piņata parties away from picturesque Piņata Island, and Mt. Erupto is an active volcano on Piņata Island), send it to the Daystrom Institute for additional analyses, or perform other indecencies on it that a flashlight in a sturdier plastic or metal body might have to have performed on it. Therefore, this section of the Nat. Pen Co. Custom-Engraveable LED Flashlight's web page will seem a bit more bare than this section of the web page on a page about a flashlight in a sturdier plastic or metal body.

Having said that, I did perform a slightly modified form of, "The Smack Test" on it; this is my normal test but performed in such a manner that I was a bit less heavy-handed than usual. I also performed, "The Drop Test" on the Nat. Pen Co. Custom-Engraveable LED Flashlight, in which I dropped it onto concrete from chest-height two times. Surprisingly, I only found some very minor denting on the edges of the bezel & tailcap where impact with the concrete occurred. No optical or electrical malfunctions were detected.

The primary purpose of this test is not necessarily to see if the exterior of the flashlight would be damaged; it's more about the internal components which would be subject to a high shock load ("G force") every time it strikes the concrete.

"The Toliet Test" would be rather inappropriate here because the product failed, "The Suction Test" quite handily. That is to say, the product demonstrated rather significant air leakage when the tailcap was removed and then the barrel suctioned.

Photograph of the beam terminus on the test target at ~12".
Light is a little less bluish than this photograph depicts.
Measures 4,560mcd on an Amprobe LM631A light meter.

Spectrographic analysis
Spectrographic analysis of the LEDs in this product.

Spectrographic analysis
Spectrographic analysis of the LEDs in this product; spectrometer's response narrowed to a band between 445nm and 455nm to pinpoint native emission peak wavelength, which is 450.470nm.

The raw spectrometer data (comma-delimited that can be loaded into Excel) is at

USB2000 Spectrometer graciously donated by P.L.

A beam cross-sectional analysis would normally appear here, but the computer hosting my ProMetric beam cross-sectional analyser is on the rag again.

Test unit was sent by and was received on the afternoon of 07-09-13

UPDATE: 08-23-13
Figured out what the current per LED is (a truly tiny 2.90mA), so they'll have extremely long, comfortable lives in this flashlight.

UPDATE: 10-16-13
The tailcap pushbutton switch has gone to pot, leaving this product totally inert.
Therefore, the dreadful, "Failed or was destroyed during/after testing" icon will be appended to its listing on this website, denoting the fact that the product is no longer functional.
Shame too, as I rather liked this little light; it saw daily use and was still on its first set of batteries.

Has phosphor white LEDs, which was a bit unexpected given the price & source
Current usage is nice & low, which is a refreshing change from other button cell lights I've tested

Light is a bit on the bluish (cool) side
Unit has a bit of a "cheap" feel to it (but given the price, this is to be expected!)

Unit is not very water-resistant and not submersible at all

    PRODUCT TYPE: Custom-engraveable keychain LED flashlight
    LAMP TYPE: 5mm white LED
    No. OF LAMPS: 3
    BEAM TYPE: Medium spot w/ soft corona
    SWITCH TYPE: Pushbutton switch on/off on tailcap
    CASE MATERIAL: Metal & plastic
    BEZEL: N/A
    BATTERY: 4x LR44 button cells
    WATER- AND DIET CHERRY COKE-RESISTANT: Light splatter-resistance at maximum
    ACCESSORIES: 4x LR44 button cells, medium split-ring on a swivel
    SIZE: 69mm L x 15.50mm Dia.
    WEIGHT: 21.90g (0.770 oz.) incl. batteries
    COUNTRY OF MANUFACTURE: Unknown; though presumably China, Taiwan, or Hong Kong
    WARRANTY: Not stated


    Star RatingStar Rating

Nat. Pen Co. Custom-Engraveable LED Flashlight *

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