They are ABS plastic. Not as well made as fiberglass would be but a better price. I don't plan on a lot of heavy use and so far for daily driving they work fine. I liked the side door, but have to be careful stuff doesnt fall out when you open it. What I liked the most is it had a retro kind of look and the curve and shape of them matches my bike. It was a toss up between these and the Tsukayu Strong Hardbags, but they were a bit more than I wanted to spend.
