It would seem to be some form of injection molded hard plastic.
I like them as they make cleaning a simple task,the only thing
you might want to insure is that you order the ones with 2 floor
hook holes as the DJ and presumably the Freemount now use 2.
I wanted them before the 2 hole was sold so I just moved the hook
closest to the door over,a simple task once you look at its design.
You might want to check out Husky Liners also if they are availiable
in your market area as they are also very good although I am not sure
they are availiable in any colour other than black.