At the VOA Wash DC studio site they had one of these Spencer vacuums.It was originally used to collect cuttings from a disc recorder in their Central Recording division.When the disc recorders were removed the Spencer was used as a portable vacuum for studio maintenance work.Loved using the vacuum.The Spencers and Pigs would be of same ages.The Spencer motor -like the Pigs is easy to service.I replaced the brushes in the studio Spencer machine-the brushes still could be obtained-late 80's.The only bad thing about the Spencer-it was bagless and was messy to empty.