Description The SPYDER Stinger Step Drill Bit Mach-Blue™ Armor Plated high speed steel (HSS) step drill bits are high-performance metal drilling bits that provide exceptional quality and durability, drilling performance, and value. The Mach-Blue™ Armor Plating combined with the advanced M-series alloy tool steel construction and proprietary heat treatment make these bits truly revolutionary they retain sharper cutting edges for longer, have reduced heat build-up and cutting friction, and increased durability, rigidity, and breakage resistance. The SPYDER Stinger Step Drill Bits are incredibly durable bits are the pro’s choice for precision drilling, extended bit life, and value. Ideal for electrical work and other applications in sheet metals, including enlarging existing holes.