A new numbering system, printed on packet envelopes, was instituted beginning with the S4 style. This numbering system persisted through V2 style packet production and into the early blisterpacks. The new numbering system also was used for the few single reels published from the mid-1950s onward. In some cases these reels were stand-alone titles, such as B6551, Vanguard Launching at Cape Canaveral. The exterior design of View-Master packet envelopes evolved greatly over the years in reponse to marketing needs and changes in company ownership.
Collectors often try to acquire their favorite titles in every known variant.