Review on Efficient Drilling Made Easy With Yangoutool Step Drill Set - 10 Steps From 1/4-1-3/8 Inches With Protective Plastic Case by Heath Cullinan

I was looking for a similar product at my hardware store for a project I was working on where I had to make a big hole in a metal sheet to a specific metric measurement, but I live in America and not only are all the expanding hole drill bits in the American measurement system, but they're crazy expensive at hardware stores. I put this thing through a sheet of metal that broke and melted two of my other drill bits and it's still in great condition. I don't know whether or not it will degrade over time, but for the project I bought it for, I could not have been happier.