Presa ST-243 Titanium Step Drill Bit METAL/100% Imported Drills holes in steel, copper, stainless steel, plastic, aluminum, and other thin materials Features 3/8-inch shank with 3 slip-resistant flat sides Has double flute for convenience Self-starting. Walking and center punch not required Step sizes: 1/4, 3/8, 1/2, 5/8, 3/4, 7/8, 1, 1-1/8, 1-1/4, 1-3/8-inch