The 350 was their first upright vacuum cleaner and it was engineered for commercial uses. The company understood that most cleaning staff weren't motivated to perform simple maintenance or be concerned about the operational status of the machine; their job was to clean the floor and their employer provided a machine so that they could do their job. If the machine was "complicated" for the employee to use, then the machine isn't any good. They still had to vacuum, but didn't care that the machine needed the disposable filter bag to be changed, readjusted for different floor surfaces, or that there was a clog somewhere. With that in mind, it offered a degree of functionality that didn't require the user to read an operations manual before using. It was equipped with a commercial-grade motor that could run continuously for 1000 hours or 41 days. The 350 was designed to pass the hardest test; to survive the abuse and neglect of cleaning professionals.