Grizzly jacket made of black covered heavy duck fabric and 12W corduroy. They use an original fabric that has been specially processed to give the brown duck fabric a rough and thick texture, and then they topped it with black. With friction and time, the black part will slowly be removed, revealing the underlying brown base. Based on the design of a grizzly jacket (which was traditionally made of leather) they added some corduroy and revised the sewing specifications to create puckering that resembles a cotton fabric jacket.