This 17-Piece high speed steel drill bit and Super Masonry drill bit set from Mibro - a 60 plus year old company selected as one of Canada's "50 Best Managed Companies" contains 12 high speed steel drill bits (sizes 1/16-Inch, 5/64-Inch, 3/32-Inch, 7/64-Inch, 1/8-Inch, 9/64-Inch, 5/32-Inch, 11/64-Inch, 3/16-Inch, 13/64-Inch, 7/32-Inch, 1/4-Inch) and 5 masonry drill bits (sizes 1/8-Inch, 3/16-Inch, 1/4-Inch, 5/16-Inch, 3/8-Inch). This is an ideal set for the home and "Do it yourself" person. With a selection for a wide number of projects. The general purpose drill bits are designed to drill a variety of materials like metal, wood, and plastic ( they are not designed for drilling stone or concrete). They have a 135 degree split tip to prevent "skating" on hard materials. The "Super" masonry bits have a hard carbide tip which extends its service life as you drill through brick, stone or concrete. The set comes in a convenient storage case that has tiltable inserts for easy access to the bits and rubberized grip panels for easy handling. If you plan to drill in harder metals like stainless steel or your use is mostly drilling metal you should consider Mibro's Cobalt drill bits item 492470.