A multi-sided bellows cover has panel sections formed of extruded plastic panels that are connected end-to-end by bead-in-slot connections. The panel sections can be made of one or more rigid wall sections that are connected at the fold lines by flexible web sections or by the bead-in-slot connection. The panel sections are integrally molded by extrusion, and many serial wall sections alternating with web sections may be integrally co-extruded with one another.