These bits have a metal body that does not close easily, making the bits difficult to remove and replace. On the other hand, I know this case will last and after using it a few times I'm used to taking it out and putting it back in. As for the jets, they're the best I've ever used. I can say they will be there for years to come. I used them to drill through hardwood, a steel door to add a peep hole, and concrete to bolt the machine table to the floor. I always get nervous about small parts but not these ones, very happy with the quality! I would definitely buy another set although I don't know if I have to.