The 3 pc. Step Drill Set includes 3 sepeate bits, ranging from 1/8" to 3/4". Bit one: 13 sizes from 1/8" to 1/2". Bit two: 6 sizes from 3/16" to 1/2". Bit three: 9 sizes from 1/4" to 3/4". High speed steel with titanium finish. Drill multiple sizes with each bit. 28 hole sizes in 3 bits