I love setting my automatic watches myself as many of them gain or lose enough time to drive me crazy, even the most expensive ones. The rear screws come with micro screws that I often lose or snap off. This set of micro screws was the answer to my problem. Jewelers never helped. In general they should not be handled roughly, otherwise they may break or fall off as they are tiny and therefore somewhat brittle. These screws are as good as anything I've used and were a great purchase for me.