The K Tool International Step Drill Bit Set, No. KTI71233, includes three drill bits: 1/8” to 1/2”, 3/16” to 1/2” and 1/4” to 3/4”. These step drill bits are manufactured of high-speed steel (HSS) 4241 and have a titanium coat. The bits come with a one year warranty. Individual bits available: Step Drill Bit 1/8” to 1/2” (No.KTI71235), 3/16” to 1/2” (No. KTI71236) and 1/4” to 3/4” (No. KTI71237).