Mark-Lite 'Fire Fly', retail $26.95 (
Manufactured by Tektite
Last updated: 04-02-09

LED Light

The Mark-Lite Fire Fly is a small, durable LED marker light. Powered by a pair of discreet "N" cells, five orangish-red LEDs blink in a pseudo-random pattern in the clear wand atop the sturdy plastic body. It is designed as a marker light or visibility aid, not as an LED flashlight.


The Fire Fly comes ready to use. To activate the blinking LEDs, give the clear top a clockwise twist until the LEDs come on; to turn the unit off, unscrew the top a bit until the LEDs go out.

A Velcro brand strap is included; this allows you to affix the Fire Fly to your arm for nighttime jogging or affix it to any other small-diameter (around 6" diameter or less) object like a tent pole, tree branch, fence post, bicycle frame, part of a boat or buoy, or anything else like that. Place the Fire Fly anywhere you need a marker light.

The Fire Fly uses a pair of alkaline "N" cells for power.

Unscrew the clear wand until it comes off.
Set it aside where it will not get stepped on or fall in the toliet.

Dump out the dead N cells and dispose of or recycle them as you see fit.

Place two new "N" cells, button-end (+) positive up, into the body.

Screw the wand back on, and unscrew it slightly when your Fire Fly springs to life, and that oughta do it.

Published battery life is 100 hours of continuous use.

The Fire Fly is a small and reasonably durable instrument. The body is composed of ABS plastic and the wand is made of clear polycarbonate. The small size should help with durability, but a fall head-first *could* crack the clear wand.
The LED board inside does rattle a bit when the wand is tapped - but because the movement is on the millimeter scale, no harm should befall it unless you just sit there and beat the living tweedle out of it for a long period of time.

It is waterproof to 1,000 feet, but it will sink if dropped in water. That was confirmed a moment ago in the fishtank. :) A light meant to be used for, among other things, as a marker for a buoy or as a diver-down marker should be able to float. :-O But the Velcro strap should hold it fast to whatever you fasten it to.
I have been told that divers usually prefer a light that sinks when dropped, so this may not be an issue for most.

Two O-rings seal out the nasties, and they can be seen through the clear wand/bezel assembly so you know if you got a good seal or not before it's too late.

The Fire Fly isn't blinding bright, but it should be visible in good conditions for a respectable distance - perhaps half a mile or more in darkness. The orange LEDs should stand out against darkness quite well.

One thing I noticed right away is that the N cells fit rather loosely inside the body; as the body appears to have originally been made for a single "AA" cell which is larger in diameter. If this is bothersome to you, wrapping a business card or similar material around the batteries to increase their diameter should help eliminate the rattle.

Spectrographic plot
Spectrographic analysis of the LEDs in the Fire Fly.

Spectrographic plot
Spectrographic analysis of the fluorescence of the outer casing of the Fire Fly when irradiated with the Handheld Blue (violet-emitting) Laser Module.

USB2000 spectrometer graciously donated by P.L.

WMP movie (.avi extension) showing the Fire Fly blinking happily away.
This clip is approximately 0.7069 megabytes (729,006 bytes) in length; dial-up users please be aware.
It will take no less than four minutes to load at 48.0Kbps.
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Test sample was received sometime in mid-May 2001.

Test sample was dunked in a fishtank but was retrieved immediately. A longer immersion test will be conducted before this review is complete. Sample was also tossed to the floor from about 3 feet and suffered no damage. Any updates related to this review will be posted as they happen.

Compact, durable package.
LED color & blinking pattern seems odd enough to ensure visibility.
Waterproof to 1,000'.
Long battery life considering the size of the cells.
Excellent warranty coverage

Sinks like a rock.
LEDs could have been brighter.
Housing seems a bit too big for the batteries.

    PRODUCT TYPE: LED Marker Light
    LAMP TYPE: Orangish-red LED
    No. OF LAMPS: 5
    SWITCH TYPE: Twist bezel on/off
    CASE MATERIAL: ABS plastic
    BEZEL: Plastic; clear Lexan cone with LEDs and PCB inside
    BATTERY: 2x N cells
    CURRENT CONSUMPTION: Unknown/unable to measure
    SUBMERSIBLE: Yes, submersible to 1,000'
    ACCESSORIES: Velcro strap
    WARRANTY: Lifetime


    Star Rating


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