Drill-Tec Steel Plates are made of Galvalume® coated steel. The round design provides an even distribution of loads and eliminates sharp corners that can damage the insulation or membrane. Drill-Tec™ Plates should be used for singleply membranes for lap and seam attachments. Drill-Tec™ Plates should be used for insulation and cover board attachment. These plates are designed to be used with Drill-Tec™ Fasteners.