This is a classic Easy-Wringer wash tub from the early 1900s. Before electric washers, people filled this galvanized metal bucket with hot soapy water and scrubbed clothes by hand using a washboard.
The central post was made to attach a hand-crank wringer (two rollers that squeezed the water out of clothes). After washing, you’d feed the wet laundry through the wringer to remove most of the water before hanging it to dry.
It made laundry day a little easier than wringing everything by hand, but it was still hard physical work. Many grandparents used these daily!

