4241 High-Speed Steel Step-Drill Bit - withstand higher temps without losing its hardness which last longer than standard carbon bits. Sizes 1/4" to 1 3/8". Will work on metal, stainless steel, wood, plastic, copper, and brass. Laser-etched hole size are easy-to-read. Fast-starting, non-walking drill tip. The two flute design cuts faster and keep bit cooler.