Kukla, Fran and Ollie
Tru-Vue 3D Stereo Card
Up until the 1960s, ViewMaster had some healthy competition from the Tru-Vue Company of Beaverton, Oregon.  Tru-Vue also offered seven stereo pictures per card, but unfortunately, Tru-Vue did not use Kodachrome.  As a result, all Tru-Vue cards have turned "red" to varying degrees.  The card below is one of the best I've seen.
The "Kukla, Fran and Ollie" card has a copyright date of 1953, and was available individually or as part of the "Televison and Radio Personalities" set, which included cards for "Buck Rogers" and "Wild Bill Hickock" (played by Guy Madison, shown modeling the Tru-Vue).  The drawings on the card itself are taken from the official KFO letterhead.

Here's my clumsy attempt to blow up the pictures - trust me, they are sharp and bright when viewed with an authentic bakelite Tru-Vue viewer!  (The picture order is from bottom to top.)