The Duro-Last Metal Plate is a square galvalume plate. Galvalume has proven weatherability and resiliency. The configuration of the ribs and the hole is used to prevent the screw head from coming in contact with the Duro-Last roofing membrane. Duro-Last Metal Plates are stamped to include a recessed hole in the center and a series of ribs for added strength. The Duro-Last Metal Plate is a long-lasting and durable plate that is available only from Duro-Last, Inc.