Timco LW38S Exterior Wing Tip Self Drilling Screw; Countersunk Head; Silver Ruspert; Maximum Fixture Thickness 21mm; Drilling Capacity 3.0mm; 4.8 x 38mmPhillips recess wing tip self-drilling screws for light section steel.Countersunk Ribbed Head, with 6 small ribs on the countersink to assist completion of countersinking.Coarse self-tapping thread.Self-Drill Point for drilling into metals without the need for pre-drilling inc. wings.Made from silver ruspert for exterior use.