European Hardwoods Nemschoff Mortise and Tenon Construction 60-92W has molded plywood seat and back Wipe-out design on 61-92U 61-92U has Spring Seat Construction Plastic Rubber Cushioned Glides Low formaldehyde emissions Nemschoff healthcare finishes for heavy use and harsh cleaning Certified to meet CTB 133/ASTM E-1537 with most fabrics Lifetime Warranty