Hi Billy,
For easier future reference I am answering your message on thread 44351 here.
How true that the Imperial name was used by a variety of companies in advertising and branding.
As for the box tops I believe they were 660 cubic inches (11.4 quarts) in capacity compared to the standard 560 cu. in. (9.7 quarts). I presume they benefited airflow, but I'll yield to others who have more insight. They were also likely designed to enhance the cleaners' appearance when they debuted with the Model 270 in 1968. I read & saw in other threads that they were factory-installed on the upper-end models and Wide Tracks from that time until their limited durability issues were discovered causing their disuse circa 1980.
In comparison, Hoover's bag jackets were 9-quart and 13.5-quart.
I was unable to locate a newspaper advertisement showing the Sanitaire Wide Track Model SC698-A from 1977 but did find one that referenced it without identification. That would have been the box top model. I'm not sure if that was also on the Model SC698-B, but a 1981 ad featuring the SC699 shows the standard pocketbook fold top style.


For easier future reference I am answering your message on thread 44351 here.
How true that the Imperial name was used by a variety of companies in advertising and branding.
As for the box tops I believe they were 660 cubic inches (11.4 quarts) in capacity compared to the standard 560 cu. in. (9.7 quarts). I presume they benefited airflow, but I'll yield to others who have more insight. They were also likely designed to enhance the cleaners' appearance when they debuted with the Model 270 in 1968. I read & saw in other threads that they were factory-installed on the upper-end models and Wide Tracks from that time until their limited durability issues were discovered causing their disuse circa 1980.
In comparison, Hoover's bag jackets were 9-quart and 13.5-quart.
I was unable to locate a newspaper advertisement showing the Sanitaire Wide Track Model SC698-A from 1977 but did find one that referenced it without identification. That would have been the box top model. I'm not sure if that was also on the Model SC698-B, but a 1981 ad featuring the SC699 shows the standard pocketbook fold top style.

