SCI A2 stainless steel exterior high tech cladding screws with countersunk head. Special Geometry  Self-perforating tip with setback notch, asymmetric "umbrella" thread, elongated cutter, underhead ribs High Tech Special geometries and treatments provide mechanical resistance that is greater than stainless steel in the same class Stainless Steel A2 AISI304 (A2) stainless steel for high corrosion resistance Field of Use  Exterior use; appropriate for service classes 1, 2 and 3 Aggressive Environments  The high corrosion resistance stainless steel allows efficient fastening even in very aggressive environments