All Known Surviving TOS Tricorders

This content represents the consensus opinion of the world-class experts at the TrekPropZone board - used here with permission - with their research being managed by Don Hillenbrand toward his eventual goal of creating a sister website to ours on the classic tricorders.

Should you have any questions about authentic TOS tricorder props, feel free to contact Don through his blog at

Shortly into production, Wah Chang was asked to come up with a prop that would be some manner of recorder. This was his sketch:

Soon after, the device was apparently reimagined as a more versatile recorder./.scanner./.computer (a "tri"-corder), essential on any away mission, so Wah simply rejiggered his design slightly to reflect those broader capacities:

Screencap study has firmly revealed a total of seven complete tricorders were made during the series, in three separate batches: 1) two "Wah" Kydex units, 2) three fiberglass units and 3) two leatherette units – each discussed below:


Using the same black Kydex plastic he utilized a few weeks prior on his comms, Wah created two units:

The swiveling top’s control panel, with its view screen (a back-painted, heat-slumped clear plastic), incorporated the same Aurora slot car wheels (as knobs) and transistor radio grill (as its rectangular “vent)” that he used in his communicators, though the indicator lights were, instead of Swarovski rhinestones, gemstone-capped Art Deco-styled watch winder crowns:

In the next compartment down was a rack of "memory disks" – actually an aluminum tube with lathed grooves, except for the end one on the right. That one was almost certainly removable, though never done on TV or imaged in any photos. To the side of those is a static circular moiré element, like in the communicator. It had no illustrated use on the show, nor have hobbyists ever agreed as to what it's imaginary function was. It just looked cool:

The third compartment at the bottom was empty, though could be opened for storage. This capacity was also underutilized, perhaps seen only a few times when McCoy stashed away his medical scanner. While the tricorder had an appropriately high-tech appearance, aspects of its design may have ultimately exceeded the more-basic needs on set. The memory disk was reported to have rattled around inside, and evidence shows the middle door had trouble staying shut. The crew used globs of putty or even at least once (below) a wedge of cardboard to keep them closed:

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An artistic habit of Wah had him adorning each of the multiple iterations of his props slightly differently, even when convention would have them be identical. Bless him for that, as it allows us to easily identify and track each unit today. So here's how the first two tricorders looked when they arrived fresh on the set:

This above unit is by far the best know tricorder, having been photographed the most, and thus is almost exclusively the one that gets copied (or forged). The three watch crowns are blue sapphire, and the "X" moiré pattern in the circular element came from the overlapping of two Edmund Scientific patterns Wah earlier used in his hero communicators, simply cut further away from the radiating center of those printed images. Plus the outside compartment handles are straight aluminum strips slotted into the doors – note above the intense finger grip needed to open it. As a result, all others had “L”-shaped handles.

The four differences that set Wah's less-famous second tricorder apart are: 1) the mixed color watch crowns (emerald-ruby-sapphire), 2) the bent “L”-shaped door handles, 3) a small black electrical slide-switch (never connected to anything as far as we know) atop the right side of the main crossbar, and 4) the radiating-prism disk in the mid-compartment's circular element. This was probably a Jewelarama, also from Edmund Scientific, which were incorporated into pendants, pins and earrings of the day. Also observe more clearly in the above-left screencap the gap between the unitized rack of memory disks on the left and the separate one on the right.

The look of these props, however, was about to change...

Approaching the end of Season 1, it was decided extra tricorders were needed. The studio’s prop shop took apart at least the "A" unit (or maybe both) to help make their copies - in fiberglass, as discussed below - and once done they reassembled the original(s), albeit poorly, with wide gaps showing in "A's" seams. Then, some months later during the break between the first and second seasons, Wah's two were again disassembled and put back together, only this time with significant alterations. The control panel of “A” went into the body of “B” (and vice versa), so now the crossbar black switch is seen with the all-blue watch crowns. Also, more dramatically, the guts of both middle compartments were discarded, never to be seen again – in these or any other copies. This means that ANY alleged “screen-used” tricorder today that has its disk rack and moiré element is an absolute fake.

Also minorly on the one above, the square vent grill in the control panel was replaced with a darker, denser gold metal mesh.

After the remixing of parts, this second unit was seen for certain only once more; in a great close-up in “That Which Survives.” It was used by the doomed geologist, hence the name “geological.” For this episode they filled the middle compartment with a blinking light panel and oddly some small portion of a steel camshaft, oriented vertically on the left. And there’s the gummy blob on the open door, used to keep it normally closed. A wire obviously needed to exit the prop to power the blinking bulb, but no one knows if they drilled a hole in the back or just snaked it through an existing gap somewhere.


Using their molds of Wah’s Kydex parts, the studio shop cast a demonstrable total of three in fiberglass. The control panel features crude knobs, a gold-painted fiberglass fabric in the square vent, and most notably – large hat pins for the three “lights.” It’s obvious the Desilu guys had no clue at the time what Wah used there for his indicator lights, but what’s nice for us is they (similar to Wah) arranged the pins in different color sequences in all three tricorders, making it possible to ID each in screencaps today.

More easy tells vs. the Kydex units: the top hood's side edge angle differs, and the straps are black on both sides instead of black./.tan:

The above prop is on display at the MoPOP museum in Seattle.


Season 3 saw two more tricorders appear, presumably also made by the studio shop. Instead of Kydex or fiberglass, though, the body's exterior is a thin leather-ish material stretched over wood panels. At least this time they replicated the indicator lights with jeweled watch crowns (again differing in color arrangement) and the control knobs are machined metal to match Wah’s original (slot car wheel) knobs.


There was also seen a few times a crude stunt version, likely just a cardboard box or chunk of foam wrapped in black tape with painted lines. Nobody has any notion it actually survived:


Inquiries on surviving original TOS props can also be sent to Kevin H., owner of the TrekPropZone board, at

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