This is a set of universal bits for drilling hard metals. Many years ago I bought a set of large handyman bits that can drill through metals and I still have them. The only problem is that the tiny parts break easily. Even if you handle them carefully, sometimes when they break through at the end of a dive, there is a slight twist and they break. That's why it's great to have a backup set to fill up. They perfectly meet all requirements. However, they do come in a nice hard plastic carrying case, so they also work well as a standalone set. There is a big difference between hardened metal and unhardened metal. I just replaced my old fashioned garage door tension spring set with a Clopay EX Set Torsion Tube system and had to drill through the extra hardened steel into the spacers. It took a lot of effort, but it went smoothly. You should start with a smaller drill like 1/8" to create a pilot hole and then you can use a larger 3/*" for example. against the big boys is handy Good performance Comes in a convenient carrying case, all at an affordable price.