Luthite is composed of an unsaturated compound polyurethane resin and an inorganic filler material which are combined with a hardener to create a material that has a specific gravity which is similar to that of wood. In addition to being less expensive and more consistent than wood, luthite can be molded into shapes that would be difficult to mill from solid wood. Resoncast is another man-made material that Ibanez has employed to create guitar bodies.