Cordless Expert MouseŽ (Trackball), retail $99.99 (
Manufactured by Kensington (
Last updated 05-07-10

This isn't a laser, flashlight, or other product specifically designed to produce light, but since it uses an LED and that lamp is rather critical to its functionality, I figured "what the H-E-Double-Bendy-Straws" - I'd probably get eternal darnation if I failed to add it to this website because of that LED in it anyway. The LED plays an extremely critical role in this product's functionality; it would be rather difficult to emulate its function without an LED.

This is a cordless four-button computer trackball that uses an optical tracking mechanism rather than a ball that rolls on a mousepad (or "mousemat" for our UK friends). A rotating disc around the ball allows you to easily scroll up & down documents or web pages that are longer than a single screen -- this very web page is a prime example here.

 Size of product w/hand to show scale SIZE

This trackball is actually quite easy to use.

Install batteries in the trackball first, and THEN you can go waste that phoney "policeman" in Wolfenstein 3D.

Plug the cord on the receiver base (the disk-shaped thing) into any free USB port on your desktop or laptop computer. The computer (assuming it uses the Windows XP or newer operating system) should almost immediately "sense" its presence and automatically install the correct driver.

I do not know the installation procedure for an Apple Macintosh computer (advertised to be compatible with this product) because I do not own or have access to one.

At this point, the trackball should now be working.

The buttons on this trackball are:
  • Upper left:   Acts like the center (scroll) button on a traditonal mouse.
  • Lower left:   Acts like the left button on a traditonal mouse.
  • Upper right: Acts like hitting the "Back" button on a web browser.
  • Lower right: Acts like the right button on a traditonal mouse.
To use the scroll wheel encircling the ball: spin it clockwise (as though tightening it) to scroll down, and spin it counterclockwise {or "anticlockwise" if you prefer} (as though loosening it) to scroll up.

To change the batteries in the Expert MouseŽ when they poop out, turn the unit upside-down while holding your hand on the ball itself; at this point, let the ball fall into that hand and set it aside -- or throw it rather hard at a freestanding porcelain lavatory (bathroom sink) if you like to hear the sound of breaking porcelain!!!

Unclip the battery door, remove it, and set it aside.

If necessary, remove the two used-up old rotten C cells from the compartment, and dispose of or recycle them as you see fit.

Insert two new C cells into the compartment as follows: place one cell in the left side of the compartment orienting it so that its nipple-end (+) positive faces the right, and push that cell to the right when it is all the way in. Place the other C cell in the same way, and snap it down so that it has the same position as the first C cell.

Snap the battery door back on, turn the unit over, and carefully place the ball back in the hole for it.
Aren't you glad that you didn't huck that ball at a poor, innocent, helpless, defenseless lavatory now?

Unable to measure current usage due to how the product was constructed.

The Expert MouseŽ is designed to be a computer peripheral, not a flashlight meant to be carried around, thrashed, 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 front porch, let my mother's big dog's ghost or my sister's kitty cats spring a leak (uranate) on it, run over it with a 450lb Celebrity motorised wheelchair, stomp on it, use a medium or large 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 (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 shoot 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 analysis, or perform other indecencies on it that a flashlight might have to have performed on it. So this section of the web page will be ***SIGNIFICANTLY*** more bare than this section of the web page on a page about a flashlight.

In fact, that photograph and three spectrographic analyses below may very well be it.

"Beam" photograph on the test target at 12".
This light is not designed to be seen, so this photograph really wasn't absolutely, positively, 100% necessary.

Spectrographic analysis
Spectrographic analysis of the red LED in this product.

Spectrographic analysis
Same as above; newer spectrometer software & settings used.

Spectrographic analysis
Spectrographic analysis of the yellow-green LED on the receiver disc.

USB2000 spectrometer graciously donated by P.L.

Product was given to me by a CPF Marketplace member on 02-19-08.

Product was made in China.
A product's country of origin really does matter to some people, which is why I published it on this web page.

UPDATE: 00-00-00

    MANUFACTURER: Kensington
    PRODUCT TYPE: USB cordless trackball
    No. OF LAMPS: 2
    SWITCH TYPE: Momentary pushbutton switches
    CASE MATERIAL: Plastic
    BEZEL: N/A
    BATTERY: 2x C cells
    CURRENT CONSUMPTION: Unknown/unable to measure
    WATER- AND URANATION-RESISTANT: Light splatter-resistant at maximum
    ACCESSORIES: USB receiver
    WARRANTY: 5 years


    Product was not intended to be a light-emitter, so the conventional "star" rating will not be used.

Cordless Expert MouseŽ (Trackball) *

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