All drill in the package were usable, some common sizes (0.5mm, 1mm, 1.5mm) even duplicated. Whether this is to pack error or intentional redundancy I can not say, however.
For drilling all small 1mm I strongly recommend a drill holder with appropriate management, otherwise break the drill immediately.
For normal steel and aluminum drill the hold about 100 drilling (estimated). In hardened steel, for the titanium-coated drill are actually, after a 4-5 drilling the end is near and the coating off. Since I needed only 5 holes and had 7 no longer even expect there 5 Star.
However, a shortcoming I would like to mention: The package is very used to. You have to first turn down the tab before you can move the template to drill. For people without 100% eyesight reading the drill lettering is almost impossible.
