Heavy-Duty Cushion Support Keeps Furniture Firm. End sagging cushions Relax in comfort. Chair Size (21"x22") Relax and enjoy the solid support of a new piece of furniture. If your sofa, or love seat and chair is sagging don't throw them out, use our cushion support. Feels great on a sore back. Just slip under any cushion to provide solid support. Made from Firm Cardboard to support any chair. Must try it-to believe it.