With this oversized backrest, you can provide your entire back with the comfort and support it deserves. The high-density, medical-grade, anti-allergenic foam will keep its shape to keep you comfortable for long periods of time. The elastic strap adjusts to fit any chair and holds the backrest firmly and securely in place. High-density medical-grade, anti-allergenic foam Elastic strap keeps backrest in place Full-size zipper Machine-washable, 100% polyester velour cover