It's not a knock off sanitaire The motor is bigger and I could be wrong but NSS has something to do with producing it. If anything it's like a Montgomery Ward type but a bigger motor.
If you want to see a knockoff go look at bissells new commercial lineup there knock offs.
It is a economical version of the Well known Eureka Sanitaire vacuums for the commercial market. Parts between the two are interchange able. We have used them many years ago. Bissell has a similar vacuum.
i think from 1987-1990 my dad got same one late 80 and it was new we use 5 or 8 years doing office cleaning my was 5.5 amp motor and sanitaire part do work with it
what interesting is bag has different dirt pocket design it has cloth tube come up from the middle
where drit come out fall around tube that pocket and tube konck side of bag get dust off
The bag is odd, there's a name on it of Vibra Kleen Venturi. There is a sateen like material tube in it. It does seem powerful and is in really good condition, I doubt it saw heavy commercial use.