Improves Seating Posture While Providing Back Support And Comfort Durable Masonite Board Sercured On Back Of Foam Core Prevents Hammocking In Sling-back Wheelchairs Conforms To Provide Support To The Lumbar Region Sealed Liner Protects Foam Core From Moisture Has A Non-slip Vinyl Back To Prevent The Cushion From Sliding Weight Capacity: 300 Lbs. Limited 18 Month Limited Warranty On Cover And Cushion Compare To Jay Basic Back