I love my Water-Matics. I have one of the first, turquoise and chrome models, made in Canada (the original manufacturer). They were designed to compete with Rainbow and Farifax. The Water-Matic doesn't use water as a filter, but it CAN be used as a wet-vac.
The oldest Water-Matic I have that was made in the USA is the Water-Matic III. It did not have an electric hose, nor a headlight on the power nozzle.
The Water-Matic V was the next model.
When SMI got it, they changed the electric hose to make it 'direct connect' at the wand end. They also offered a model with the Wessel-Werks nozzle, which made for an awesome cleaning system.
BEFORE I was President of the VCCC, I had a convention in St. Louis and everyone came to my home for the Cleaning Contest. I demonstrated the new (at that time) Water-Matic III, filling it completely with dirt and demonstrating it had very little loss of airflow and suction. Wonderful design.
Thanks for the Video, brought back memories. I haven't used my Water-Matics in years. Think I know what my next Daily Driver is going to be.