It is NOT something I would call "light weight". In fact, the RCA Whirlpool Imperial Mark 12, along with it's sister, the Kenmore Whispertone, are among the heaviest cleaners when loaded with their attachments and wands.
I love the brochure Charles posted. While RCA Whirlpool's claim to be the "first" power nozzle canister isn't actually true (Lewyt beat it by a year), it was indeed the second (Electrolux was third).
I notice the Brochure and the magazine ad were from different years. The last photo is the magazine ad, AFTER the electric hose had been invented. Probably from 1960, which is the first year SEARS had the electric hose. Whirlpool made Kenmore vacuums for Sears.