I remember my old godmother using one like this and also had one on our first (second-hand) washing machine which was built in on account of the fact that spin dryers had not yet been invented!
My Auntie s used to have one, Mondays was wash day, the water was heated in a tub for hours, then the washing was put in to soak, then used a washboard, then rinsed and finally thro the wringer. ( feel like I been thro the wringer sometimes read# )