Abstract: A cassette for supporting substrates and an elongated rib therefor is described and represents a further improvement in the previously proposed elongated rib systems of the prior art and is designed particularly to preclude deflection and dampen vibrations of loaded substrates. The elongated ribs for the cassette project from side panels utilizing an elongated rib structure including three segments; namely, a base resin body, a bar-like intermediate resin body extending from the base resin body, and a terminal resin body disposed at the forward end of the intermediate resin body. Preferably, the elongated rib structure includes a linearreinforcing member inserted fromthe base resin body to the intermediate resin body or, alternatively, from the base resin body through the intermediate resin body to the terminal resin body.