The interesting thing on this photo is the pleated white filter showing through the slots around the motor. This is the final exhaust for the air exiting the system back into the room. By the time the air reaches here, it has been through the big canister filters above it (next photo) and virtually all dirt is removed. This filter matters if someone has allergy problems and you want to catch the finest pollen.
Finally figured it out. The canister is negative pressured. It sucks air up from the floor (rug beaters) and into this canister (left arrow), and up from the attachment hose (right arrow) and into the canister. The negative pressure -- the big suck -- is through the hole in the middle of the bottom. To get there, the air must pass through the main filter (removed; on floor).
Looking up inside main filter. Like the one on my big shop vac, this will last forever unless you get it wet or torn while cleaning it.
The wheel height is not adjustable since the plastic arm (arrow) broke shortly after we purchased the vacuum. The long steel drill bit under the silver duct tape solves the problem -- it's unbreakable. If you want to change the height (shag rugs?), move the duct tape.
The Turbo Tool -- a turbine-driven brush for the attachment hose. Air pressure runs the turbine.
--end
Overview.