Look at that beautiful solid basket spinner tub! On this machine you place that ledge over the edge of the sink and the water is spun up over the top, onto this ledge and it falls into the sink and down the drain. I'm surprised to see that there is even a little drain at the bottom for any extra water that might be left over.
On some of these early twin tub machines, you could turn the ledge so it spins the water into the sink or back into the wash tub to save the suds.