Have bucket but no pulsator, which one do I need?

"S" style lids, both flat and crescent originally came with the older seamed bucket. While the "C" style lid came with the newer seamless bucket and need an o-ring between pulsator and post. Lids are interchangeable from one bucket to the other, however you need to match a "C" pulsator with a "C" lid and an "S" pulsator with a "S" lid. Compare this picture with your lid to determine which style pulsator you need.