Typically on American pocket watches the crown comes in the case. Then the preferred method of letting power off would be to use a bench key. I'm attaching a photograph typically that come in a set of three.  There are some other variations of how they come but typically this is what the look like a series of squares that Correspond to the typical American pocket watch sizes. Because the cases were made by other people there does tend to be a standard for how big the squares are.   A