Hello, thanks for asking about the Biagio Swivel Bar Stool, Espresso with Brown Seat. The seat of this stool is upholstered in PU leather. Bicast leather or PU leather is a material made with a split leather backing covered with a layer of polyurethane. Hence the term "PU leather", that is applied to the surface and then embossed. I hope this information is helpful to you!