I really wanted to use them in a project I was working on. After receiving and unpacking, I realized that this is garbage! If you need them to create precise holes, forget it. Bits are poor quality metal. The dots just had to be bent back to a pair. And each of them is deformed. So if you want your work to be exactly 3mm or 4mm, these cheap bits won't do it. Spend extra money on a famous brand.