In 1960, Zenith also produced a limited quantity of speaker boxes called the Converta (Royal 55C) to go with the Royal 50.  It’s purpose was to convert the shirt pocket sized radio to a table radio and produce a bigger sound through it’s 4″ speaker.  It measures 6″ high, 7.5″ wide, and 3″ deep and weighed only 18 ounces.  It worked well producing a “bigger” sound, but with the radio installed, they were top heavy and not very stable.  They were made of brittle plastic and with a fall or two, the thin legs would break, making it even less stable.  It’s cost was $44.95 (I don’t know if that included the radio or not) which made it quite an expensive option and thus not a hot seller.  As a result, these are very difficult to find in good condition.

Check out these Royal 55C Converta radios.