Their small size also made them easy to mail as well as store, and soon became the defacto standard of many large & medium size offices. When new, the belts were extremely supple, and could easily be flattened into a mailing envelope or preferably a small box, with few if any consequences. Field offices could receive audiograms or even personalized audio messages/dictation in several days via the USPS..... Naturally, the Dictaphone Corp sold 10's of thousands of em !
The Dictabelt machines were built like tanks and were mechanically over-engineered to put it mildly. Other than a belt and a rubber idler wheel & replacement styli, the drive mechanism if kept lubricated and maintained, will most likely outlive many generations of potential users..... ( some yet to be born ! ). Having rebuilt and maintained many a unit, I can personally attest to the fact that Dictaphone® built one tough machine ! Short of being thrown out the window of a 5 story building (where it's not unlikely that the concrete below might sustain the most damage), the basic drive mechanism would most likely survive any torture even a "sick" demented office worker could conjure up ! By the time Dictaphone Corp switched to tape, they had by that time an understandably loyal following of Dictabelt users and a huge installed base, which made the transition to tape an easy sell. Had it not been for the Dictabelt, Dictaphone Corp probably would have gone the way of Edison. Though "built like tanks", they did however require lubrication, occasional adjustment & alignment to keep the belt tracking true on the mandrels.
Although the belts and recordings are holding up pretty well even after 50 years or so in many cases, finding a working Dictabelt machine today is quite rare. Even scrap "parts machines" are becoming hard to find. Sadly, most firms just tossed perfectly good working machines into the dumpster back in the early 60's, to make way for the new tape based dictation equipment....... (enough to make one cry today)....... Yet another case where the media again outlives the availability of the equipment on which to play it.....