(SEE AVAILABILITY ABOVE FOR ESTIMATED DELIVERY) – Solid Seat Inserts 22″W x 18″D – Solid Seat Inserts – This Solid Seat Insert is a semi – rigid foam block with a convex bottom & a flat top. The smooth, waterproof, closed – cell foam wipes clean easily. – Rolyan products are internationally licensed & manufactured for home & clinical use. Most of their products offer a lifetime warranty.