Packaged in sturdy metal index containers or shock resistant, extra-thick polyethylene carrying case. Drill bit sizes are clearly marked on inside panels for easy identification and selection. Metal panels are hinged and neatly folded into box. •For use on: Mild steel; Non-ferrous metal; Stainless steel; •Drills more holes, faster; •Heavy-duty fully ground body construction; •Special bronze SST surface treatment; .