CrazyEve 5 pcs HSS Step Drill Bit Set Titanium Coated Cone Step Drill Bit Hole Cutter Metric, Model: CS0379, Tools & Hardware store MATERIAL: High Speed Steel with Cobalt Coated. THIS SET replaces 50 individual drill sets. SELF STARTING - no need for a pilot hole. AUTOMATICALLY DEBURRS holes as you drill. COBALT COATED to reduce friction and run cooler. Size pls see description.