These are the worst drill bits I have ever bought. I ordered them for my hobby, but the drills are so blunt that they cannot drill through Styrofoam (plastic), wood, plasterboard and cardboard. CARTON! I couldn't drill through corrugated cardboard with these bits. The case is also poorly designed. I had a hard time putting the drills back in the case. DO NOT SPEND YOUR MONEY. These will be returned.