5PCS HSS Cobalt Step Drill Bit Set, designed for professional and DIY projects. This high-quality set includes 50 different hole sizes, replacing the need for multiple drill bits. Made from durable high-speed steel (HSS) with a cobalt coating, these bits ensure faster, smoother, and cooler cutting in steel, aluminum, copper, brass, stainless steel, plexiglass, wood, and laminates.