Nice, vintage, I was told prewar or around that era, ladies bike bicycle seat with the mounting bracket underneath as shown in the pictures. Seat is marked Mesinger Made in USA. I don't know much about these things, clearly. Very good shape with general wear, a tear on the underside rear lip of the seat material, some light rusting on the metal and needs a good cleaning. Zoom in for details. It's about 8 inches wide and 8 3/4 inches from front to back. Heavy.